Raymond Sultan, M.D. *
While the mitzvah of brit milah may be kept by a larger percentage of world Jewry than any other mitzvah, it does not preclude it from controversy, the most recent of which centered on the practice of metzitza b'peh. This traditional third step in the brit milah process in which blood is orally suctioned from the wound, is admittedly unfamiliar to many. In the past few years, a number of babies have contracted the herpes virus (HSV-1) shortly after circumcisions that included metzitza b'peh, and controversy arose as to whether the virus was transmitted through the metzitza procedure. The controversy that has made headlines recently with the herpes virus, made similar headlines 20 years ago with HIV and was similarly newsworthy in the 19th century when some questioned the association between metzitza and various illnesses. Today we know that a mohel could never transmit HIV to a child, and the chances of a child transmitting to the mohel are in fact quite minimal - the risk is now understood to be far less than in the past. 
The forthcoming analysis will focus on three issues: (1) What level of risk must (or may) one take upon himself in performing mitzvot? (2) Does halacha view all risks equally? Is there some minimal threshold that must be reached for the risk to become relevant? (3) How does halacha view competing risks? When can one risk outweigh the next?
I. What Is Metzitza b'Peh and Why Perform It At All?
Three components of brit milah are enumerated in the Mishna (Shabbat 19:2), explaining that the requirements of circumcision on Shabbat is no different from that during the week: "One may perform all actions necessary for circumcision on Shabbat: mohalin (cutting and removing the foreskin), por’in (folding back the underlying membrane) u-motzetzin (sucking blood from the wound)". As such, it would appear that metzitza is part of the mitzvah, similar to the other two actions with which it is grouped, namely, milah and peri’ah. However, while the Mishna (19:6) states that without peri’ah, a circumcision is invalid, it makes no such claim regarding metzitza. On the other hand, the Gemara (Shabbat 133b) quotes Rav Papa saying that a mohel who does not perform metzitza creates a danger (sakkana) and we remove him from his position.
From the days of the Ran and throughout the generations, poskim have analyzed the nature of metzitza and generally understood it in one of two ways: It is either meant as a therapy, solely to prevent an impending danger (sakkana) to the child, or aside from the therapeutic benefit, there is additionally some element of mitzvah as well. Based upon how the obligation is viewed, poskim have different opinions as to whether to allow a change from traditional metzitza b'peh, and if so, how and when.  The requirement for metzitza b'peh despite a potential danger seems to hinge upon this debate. For the many poskim who take the former view that metzitza was instituted solely as a medical therapeutic practice (and therefore not a mitzvah), there seems to be no reason to continue with metzitza b'peh today, when performing metzitza may entail a greater potential medical risk than abstaining from its performance.5,6 Moreover, even for those poskim who view metzitza specifically b’peh as being an element of mitzvah and part of Jewish heritage, there are a great many poskim who explain that applying oral suction via a tube (usually an inverted syringe) is equivalent to performing metzitza directly b’peh. Using such a tube would completely prevent transmission of any pathogen from the mohel to the child.
Why specifically use the mouth?
The very question is relevant only for those poskim who are of the opinion that metzitza is an integral part of the milah process (whether as a halacha le-Moshe mi-Sinai or otherwise) and that it must specifically be performed by direct oral suction.  The argument made for direct metzitza b'peh usually takes one of 4 forms:
1. There is a halacha le-Moshe mi-Sinai that metzitza must be specifically performed in this way (Shu”t Maharam Schik, Y.D. 245).
2. Kabbalistic rationales having to do with tikkun, a correction, or gematria, numerical value of numbers and their hidden meaning (Chida).
4. The need to maintain the unchanged integrity of revered traditions, minhag Yisrael.
Those poskim who disagree, argue about the three rationales. Many, even amongst those poskim prohibiting the use of a tube, discount the Maharam Schik’s contention that metzitza b'peh is derived from a halacha le-Moshe mi-Sinai. Furthermore, the role of kabbalistic sources in shaping normative halacha is a contentious matter and is subject to much halachic discussion. Third, these poskim contend that using a tube for hygienic reasons in no way represents a bizayon since its sole purpose to protect both the mohel and the baby from any harm and that furthermore, that using a tube can indeed provide effective suction, when placed correctly.
There are two common subtypes of the herpes simplex virus: HSV-1 and HSV-2. HSV-1 most commonly infects and resides in the oral cavity whereas HSV-2 is associated with the genital area, though each type can be found in both regions. Viral spread of infection occurs via infected salivary secretions during close contact with mucous membranes, with the recent controversy stemming from genital HSV-1 infection in children who underwent metzitza b'peh. Successful transmission results in either a symptomatic mucocutaneous infection in the mouth (cold sores) or an asymptomatic subclinical infection, as the virus hibernates behind the mouth in the trigeminal ganglion, where it can remain for life in a phase known as latency. Subsequently, reactivation of the virus into the oral cavity can occur at anytime or not at all, triggered by physical or emotional stress, fever, or even ultraviolet light. However, it most commonly occurs in the complete absence of symptoms in a select group of individuals with variable frequency.
HSV-1 infections in the adult are frequently asymptomatic, but even with clinical symptoms, are rarely a serious systemic illnesses. In contrast, HSV-1 infection in newborn usually develops in one of three patterns, which occur with roughly equal frequency: (1) Localized to the skin, eyes and mouth; (2) localized central nervous system disease, or encephalitis (15% mortality); and (3) disseminated disease involving multiple organs (57% mortality). HSV infection of the newborn even just 25 years ago was associated with a case fatality rate of 60%; today however, medications are available to alter the course of the infection if caught at an early enough stage.
Most people with HSV-1 do not even know they harbor the virus and yet viral particles could be isolated from the oral secretions of such asymptomatic individuals. These people harbor the virus in its latent state and experience asymptomatic shedding of viral particles into their mouths throughout their lives. Such shedding occurs on 1% of days among previously symptomatic 9%of adults and 5-8% of children were asymptomatic salivary excretors of HSV-1. Only about a third of seropositive individuals suffer from recurrent cold sores. The shed virus can be infectious and has been recorded as persisting for an average of 1.2 days for a healthy control group.
HSV-1 infection is quite common. Data from 1986 showed that 40-63% of all people in the United States were seropositive for HSV-1. Seropositivity in this context means having antibodies in the blood against some part of HSV-1 and is an indication that the particular host has previously encountered the virus which now likely resides within that host in latency; more recent data suggest the incidence may be as high as 70%. A 2005 Israeli paper found the unadjusted HSV-1 seroprevalence to be 59.8%. These numbers vary so greatly because of their reliance on different types of tests to determine infection rates. Recently, with the advent of technologies able to detect rather minute amounts of virus in oral secretions, it remains questionable whether such amounts are infectious to others.
To put these numbers into perspective: In a room of 500 people, 300 would have the antibody in their bloodstream and therefore the virus in latency. 100 would have occasional cold sores associated with the virus. On any given day 1 person would have detectable levels of virus in his mouth shedding asymptomatically. If that one person were a mohel performing metzitza b'peh and transmitted a viable infectious virus (though he had saliva and wine in his mouth as he made only momentary unidirectional contact), which did not simply hibernate in latency and cause the usual subclinical asymptomatic carrier state in the child, but rather overwhelmed the child’s immune system (60% of children should have protective antibodies), then 2/3 of such cases pose a combined 24% mortality which could potentially be reduced by early intervention with antiviral medication. The risk therefore, is indeed quite minimal. Moreover, there is some question as to the applicability of the quoted rates of asymptomatic shedding of virus amongst individuals who, although infected, have never been clinically symptomatic.  
Currently, the medical literature is limited to three articles of isolated case reports demonstrating an association between the practice of metzitza b'peh and infection.24,25 Retrospective case reports demonstrating association, borderon speculation and do not prove causation. Indeed, the HSV-1 virus is known to be quite hardy, but it would be difficult to assess what role, if any, salivary inhibitors of HSV-1 or wine with alcohol as an antiseptic (as is taken into the mouth of the mohel prior to metzitza) may play in prevention of person-to-person transmission. However, if a host harbors an active cold sore the risk of transmission is known to be elevated. We will therefore assume that all mohalim will follow the pesak of R. Yosef Shalom Elyashiv and refrain from performing metzitza b'peh if they have an exposed oral lesion or are knowingly symptomatically shedding virus.
This is not the proper forum to debate the merits of these scientific studies. It is important to note however, that there are still many unanswered questions and that many of these articles are not conclusive and may contain several epidemiological flaws. Nonetheless, the rest of this article will assume that there may exist some potential, as yet to be determined, risk of HSV transmission through metzitza b'peh, with the understanding that such a risk is considered questionable (safek sakkana).
When properly employed, suction generated by the mouth using a sterile tube conveys no risk of infectious disease traveling from mohel to child or child to mohel, yet some level of risk does exist in performing direct metzitza b'peh. All of the subsequent analysis assumes that a mohel who knows that he is infectious, will not perform metzitza b'peh for fear of endangering the child. Similarly, it assumes that in accordance with the pesak of R. Yosef Shalom Elyashiv, a mohel with an exposed oral lesion, will not perform metzitza b'peh either, even without any other systemic symptoms or awareness of illness. The only cases to be analyzed are those involving seemingly healthy mohalim who may nonetheless be asymptomatic carriers of infectious disease. According to the great number of poskim who feel that metzitza need not require direct oral contact, there seems to be no reason to continue to practice this method in the face of any danger whatsoever. The Shulchan Aruch (C.M. 427:10, Y.D. 116:5) records the prohibition against actively harming oneself and therefore, the question arises only for the previously mentioned poskim who argue that metzitza is integral to the milah and additionally must be [according to some only optimally] performed by direct oral contact. How and why this may be allowed will be presented below.
Must a person literally “make himself sick", so that he can perform a mitzvah? How far does preserving one’s health go in exempting a person from performing mitzvot? This issue arises a number of times in halachic discussions, in the unfortunate case where a person must choose whether to fulfill a certain mitzvah and in doing so, become physically uncomfortable or even worse, seriously ill.
a. Saving a friend’s life
The issue in question is reflected in the classic case of whether or not one may (or must) save a friend’s life from certain death when the rescue itself entails uncertainty to the life of the rescuer. Rescuing a friend from danger is a component of the mitzvah of va- hasheivota lo - “and you shall return to him” - and the broader question really hinges upon the risk that one must take in performing this mitzvah. The Beit Yosef (C.M. 426) cites the Hagahot Maimoniot (Rotzeach 1:14) quoting an unreferenced Yerushalmi that a person indeed must enter a situation of safek sakkana (uncertain danger) to save his fellow from a vaday sakkana (certain danger). Although the Beit Yosef quotes no other sources on this issue, he makes no mention of this requirement in the Shulchan Aruch. The Sema (426:2) explains that since this halacha does not appear in the Rif, Rosh, Rambam or the Tur, the Beit Yosef concluded that this stance, while noble, is not to be considered normative.
The Radbaz (Shu”t Radbaz 3:627) takes this position somewhat further when asked about a rather terrible incident where a nonJew threatened to kill a Jew unless the victim’s friend allowed his hand to be cut off or his eye gouged. Even assuming that severing a limb entails no life threatening circumstance, the Radbaz argues that such an action on the part of the friend is not required but is nonetheless considered a righteous deed. The Radbaz argues that since the Torah’s precepts are described as “darcheino’am” - ways of pleasantness - it is impossible to assume that the Torah would require a person to have his eyes gouged or his arm severed to save somebody else’s life. The Radbaz is clear however, that if the amputations involves a risk to life (as it probably did in the early sixteenth century before the advent of antibiotics and sterile technique), then one who goes through with such an action is a chassid shoteh - a deranged pious person. Many poskim derive from this responsum that normative halacha does not require a person to risk his own life to save his friend’s, even when the risk to the rescuer is only possible (safek) while the risk to the friend is certain (vaday).
b. “Three cardinal sins”
There are well known instances however, where one is obligated to risk one’s life or even give up one’s life so as not to violate certain mitzvot, namely the “three cardinal sins” of murder, idolatry and forbidden sexual relations (Shulchan Aruch Y.D. 157:1). It must be noted that even the very formulation of this category of yehareg ve-al ya’avor - be killed rather than violating the prohibition, applies specifically to passively refraining from performing these prohibitions. Halacha does not demand that a person give up his life in the active performance of a mitzvah.
Regarding such instances the Gemara (Sanhedrin 74a) explains that the Torah (VaYikra 18:5) requires “ve-chai ba-hem ve-lo she-yamut bahem” - [these are the mitzvot that] one should live through [by] them and not die by them. However, certain poskim maintain that while halacha does not require one to risk one’s life to fulfill a positive commandment, certain people may nonetheless elect to do so. Tzaddikim or other Torah leaders may take upon themselves a life-threatening danger when they feel that performing the mitzvah despite this risk will have some benefit to the greater community, especially when death is not a certainty. This permission is not widely accepted nor extended to the general public and as such has limited applicability with regard to metzitza b'peh. It seems clear therefore, that a person need not accept a risk of death in performing mitzvot.
c. Dwelling in a Sukkah
There are other, more mundane applications of this question as well. The gemara already provides a model for exempting a person from performing a mitzvah based on level of pain or discomfort that he must endure. Sukkah 26a relates that a person who is mitzta’er (pained), is exempt from dwelling (eating, sleeping) in the Sukkah. The Shulchan Aruch (640:4) limits this exemption and explains that it does not apply on the first night of the festival. The Acharonim debate whether the exemption of mitzta’er is a model to be used throughout halacha even though it is only mentioned here, or is limited to the mitzvah of sukkah. The Chelkat Yo’av (dinei ones, anaf 7) explains that for sukkah there is a unique exemption for even somebody who is suffering [or perhaps would suffer] from only minor discomfort. However, for all other mitzvot there is also an exemption of one who is also mitzta’er, albeit requiring a more substantial pain/discomfort (tza’ar gadol). Therefore, he exempts a choleh she-ein bo sakkana - a bedridden sick person whose malady poses no risk to life - from mitzvah performance. The Chelkat Yo’av agrees with Rema (640:4) that a mitzta’er is only exempt from dwelling in the sukkah, when refraining from doing so will alleviate his tza’ar. However, if one’s ailing health will not deteriorate by dwelling in the sukkah and the sukkah does not cause him any additional tza’ar, he is obligated to dwell in the sukkah. A similar paradigm should apply throughout all areas of halacha.
The Binyan Shlomo (47) following the rationale of Rabbeinu Manoach (Hil. Sukkah 6:2) argues that a mitzta’er is exempt only from the mitzvah of sukkah (at all times except for the first night), but is nonetheless obligated in all other mitzvot. In a similar manner to the Chelkat Yo’av above, the Binyan Shlomo parallels a choleh she-ein bo sakkana to a mitzta’er, but because of his understanding of the exemption of mitzta’er by sukkah, obligates a choleh she-ein bo sakkana in all other mitzvot. The Maharam Schik (Shu”t Maharam Schik O.C. 260) goes slightly further and explains that even when performing a mitzvah will certainly entail some physical harm, albeit not posing a risk to life, one is obligated to perform that mitzvah.
d. Drinking Four Cups of Wine at the Seder
This issue also arises with the requirement to drink four cups on wine at the Seder. The Shulchan Aruch (O.C. 472:10) writes that even a person who greatly dislikes wine or does not normally drink wine because it harms him (maziko), must nonetheless push himself to fulfill the mitzvah of drinking all four cups. The Mishna Berurah (472:35) limits this harm to causing physical discomfort and/or developing a subsequent headache; the obligation does not go so far as to require pushing one’s self so far becoming bedridden (yipol le-mishkav). Subsequent poskim debate whether this rule is applied to all mitzvot or is limited to drinking wine at the Seder.
The Sha’ar ha-Tziyyun (472:52) explaining the reason for the Mishna Berurah’s limitation, says that such consequences would label the drinking as not in the manner of [exhibiting] freedom (derech cheirut). It seems logical to conclude therefore, that in all other areas of halacha where this unique characteristic does not apply, one must indeed perform any mitzvah even knowing that consequently he will become so sick that he will become bedridden. R. Tzvi Pesach Frank and R. Moshe Sternbuch reject this conclusion and claim that the mitzvah of drinking the four cups of wine differs in other aspects as well and therefore has a unique limiting factor. The Shulchan Aruch (O.C. 472:10) records that one is required to go to great lengths not ordinarily required by other mitzvot to secure wine to drink at the Seder. One would have therefore thought that the stringent nature of this mitzvah would permeate all aspects of its performance and would require exerting one’s self further than required by any other mitzvah, even to the point of becoming bedridden. The requirement of derech cheirut is a reason for leniency in this stringent mitzvah that reduces the level of required exertion by drinking the four cups to the level required by all other mitzvot. The mitzvah of the four cups, in their opinion, is similar in character to all other mitzvot - none of which require pushing one’s self so far as to become bedridden.
R. Chayyim Pinchas Scheinberg argues against Rabbis Sternbuch and Frank’s logic. He cites numerous examples where the level of exertion required for fulfilling the mitzvah of the four cups is compared and otherwise viewed in parallel to several other mitzvot. If, as Rabbis Sternbuch and Frank claim, the mitzvah of the four cups is unique in its stringency, no parallel could be made between it and other mitzvot. R. Scheiberg therefore concludes that the limiting factor of derech cheirut functions to lessen the level of required exertion only by the mitzvah of the four cups. In all other mitzvot however, where this factor is irrelevant, one must exert himself so much, that he would even become bedridden as a result of performing the mitzvah at hand.
e. Spending Money on Mitzvot
R. Scheinberg raises a global argument relating to the nature of the performance of positive commandments. The Rema (O.C. 656:1) explains (based on Ketubot 50a) that a person need not spend a substantial sum of money (hon rav) to obtain the means to perform a positive commandment since a person should generally not spend [waste] more than 20% of his net worth. It follows that a person is nonetheless obligated to spend up to 20% of his wealth. The Rambam (Erchin va-Charamim 8:13) explains that this limit was set so that a person should not run the risk of becoming poor. R. Scheinberg points out that Chazal viewed the risk of poverty with great severity (ma’aviro al da’ato ve-al da’at Kono) and therefore exempted a person from mitzvot in which such a risk was apparent. Based on Shabbat 118a, the Mishna Berurah (242:1) explains that one must “make Shabbat as a weekday and not rely on receiving charity from others” means that one who is in dire financial straits is exempt from having three meals on Shabbat. The Bi’ur Halacha (656 s.v. afilu) explains that the limits and regulations regarding how far one must exert himself for Shabbat purposes apply to all other mitzvot as well. R. Scheinberg quotes the famous Gemara of Berachot 61a which explains why the Torah requires us to love Hashem both “with all our soul [body]” as well as “all our resources” (Devarim 6:5). The Gemara explains that the Torah’s admonition includes all sorts of people, those that prefer their bodies to their wealth and those that prefer their wealth to their bodies. R. Scheinberg therefore concludes that the Torah is aware of some individualistic component in this regard, and therefore is reluctant to offer a concrete method of balancing the two values.
R. Scheinberg therefore argues that there is a difference between the risk of poverty and the risk of a curable illness, with the former being far more serious. By the risk of poverty, Chazal were willing to allow the violation of a given mitzvah, because otherwise a person may unfortunately become so poor that he will be unable to fulfill any of the other mitzvot anyway. R. Scheinberg posits that an illness that “undermines the entire life of a person in all ways” and presents a risk of a person “losing his mind” (ma’aviro al da’ato ve-al da’at Kono) is parallel to the risk of poverty and one is exempt from performing any mitzvah that engenders such a risk. However, the risk of a curable illness is indeed not parallel to the risk of poverty and therefore a person must perform a mitzvah, knowing going in that there is a risk that he will become curably ill.
B. Does Halacha View all Risks Equally? Is There some Minimal Threshold That Must Be Reached for the Risk to Become Relevant?
Every action we perform entails some element of risk. Even such mundane acts as crossing the street to get to shul involve the risk of being hit by a car. Such a risk however, seems to fall off our radar, and we take no cognizance of it during our daily lives. Many people practice the custom of kissing the sefer Torah (either directly by mouth or by touching the sefer and then kissing their hand) while it is being taken to the bimah, completely disregarding the reality that numerous people have done so before them, and the sefer’s montel (cover) appears as an ideal breeding ground for various bacteria. Similarly, the halacha also seems to have some minimum threshold of risk that is acceptable or even ignored in certain cases, as is evident in numerous discussions.
enumerates various procedures which are technically forbidden, because they are
dangerous, yet, since so
many people do these things anyway, it has become common practice to permit them. Thus, the Gemara in Shabbat (129b) mentions specific days when one is forbidden from bloodletting (“leeching”). Although Fridays should be included in this list as well (similar to Tuesday, it is a multiple of three), the Gemara relates that the common practice was to perform bloodletting before Shabbat and since “many have already trodden upon it [this path]” (keivan de-dashu beih rabbim) - “Hashem protects the simple-hearted/minded” (shomer peta'im Hashem) (Tehillim 116:6). Similarly, in Yevamot (72b) there is discussion about prohibiting making a brit on cloudy days or days with a strong south wind as these circumstances present some risk of danger. Once again, the Gemara rationalizes with the same phrase - “keivan de-dashu beih rabbim”, “shomer peta'im Hashem”. In a more complex scenario, the Gemara (Yevamot 12a) records a dispute between R. Me’ir and the Sages regarding the use of certain contraceptives (moch) for women for whom pregnancy was strictly contraindicated for fear of death to her, her fetus, or her young child whom she is nursing. The Sages argue that despite this risk, such women may not use a moch and “from the Heavens they will have mercy on her", as the verse says, “shomer peta'im Hashem.”
The Gemara describes other instances when despite a perceived danger, a person may nonetheless continue a given action, relying upon divine protection. The rationale is that “people engaged in a mitzvah are not harmed” - sheluchei mitzvah einam nizokim (Pesachim 8b). Thus, the Gemara concludes that pilgrims ascending to Jerusalem for the festivals need fear no physical or monetary harm since they are engaged in a mitzvah. Similarly, poskim allow and perhaps even require performing certain mitzvot despite a known risk, since “a person who keeps the mitzvot will know no harm” (shomer mitzvah lo yeda davar ra). The Sefer Maharil permits using water left exposed overnight at the start of tekufat Nissan, despite the general prohibition of using such water, since the matzot are to be used for a mitzvah (at least matzot for the first night of Pesach), the principle of shomer mitzvah lo yeda davar ra applies. The Shulchan Aruch ha-Rav (O.C. 455:16) goes so far as to say that one is forbidden to discard this water even if other water is available since by doing so such a person denigrates the idea of shomer mitzvah lo yeda davar ra. The great majority of poskim use the phrases “shomer peta'im Hashem”, “shomer mitzvah lo yeda davar ra” and “sheluchei mitzvah einam nizokim” interchangeably. All three convey the conviction that a person engaged in a mitzvah has a certain measure of divine protection.
In the discussion that follows, we will attempt to analyze various uses of these themes and uncover some systematic approach to their application, with an eye towards determining whether the ideas expressed may legitimately be invoked for performing metzitza b'peh.
b. Mechanism and Rationales
In the course of Torat Chesed’s (Lublin) (E.H. 44) discussion of contraceptives, he attempts to provide a mechanism for the idea of shomer peta'im Hashem through a discussion of a dispute between Rashi and Ritva. He explains that Rashi believes that the three women listed in Yevamot 12b are prohibited from using moch contraceptives, since shomer peta'im Hashem and therefore, min ha- Shamayim yerachamu. The Ritva (Ketubot 39b) rejects this approach since he does not believe that Chazal would force women to accept such risks upon themselves. The Ritva opines that these women may take the precaution of using a contraceptive (moch) or alternatively, may rely upon shomer peta'im Hashem and have normal relations; the choice is left to the woman. Torat Chesed points out that there should be a parallel disagreement by performing a milah on a cloudy day (Yevamot 82a), and indeed Ritva (ad loc.) explains that on such a day a person has the option whether or not to perform the milah. The Torat Chesed argues that Rashi would disagree and, consonant with his previous stance, would argue that a person is obligated to perform a milah on a cloudy eighth day, even if it were Shabbat. This position is accepted by the Shulchan Aruch as normative.
Torat Chesed suggests that the basis for the disagreement between Rashi and Ritva is how to evaluate the reality of danger (sakkana) once Chazal invoke shomer peta'im Hashem. It would seem that according to Ritva, although there is a general prohibition to engage in risky behavior, once Chazal invoke shomer peta'im Hashem, one is permitted to continue this activity despite the inherent risk. There is no absolute requirement to perform the action, since invoking this principle does not actually diminish the real risk in any way. Rashi, on the other hand, would argue that once Chazal invoke shomer peta'im Hashem, it is as if the risk is non-existent. Although the statistical probability of incurring the danger remains, risks below some probability threshold are simply ignored by halacha. “Shomer peta'im Hashem” means that a person may engage in normal activities and not be constrained or concerned by the minute risks continually involved. This “halachic reality” is so strong as to create an obligation for a father to perform milah on his son even on a cloudy day (and even on Shabbat).
c. Calculating Minimal Risk-thresholds
Since, as noted previously, the Shulchan Aruch seems to be in accord with Rashi’s approach, it is important to quantify the riskthresholds that scan below the halachic radar. Quantitatively, there are certain guidelines to apply. The Gemara (Pesachim 8a, Kidduishin 39b) is clear that the principle of sheluchei mitzvah einam nizokim does not apply and may not be relied upon in cases where danger is prevalent (shechiach [kevia] hezeika) and the Torat Chesed (ibid.) easily extends this limitation to the question of prohibiting certain contraceptives and relying on shomer peta'im Hashem. Since he does not quantify the risk-threshold that qualifies as “prevalent", we may (rather conservatively) assume that any risk-threshold, below the level of mi’ut ha-matzui (a prevalent minority) is certainly included. This value normally ranges between 10-14.5%. R. Chayyim Ozer Grodzinski (Achi’ezer 1:23) insists that shomerpeta'im Hashem certainly overrides a mi’uta de-mi’uta - a minority of a minority, and in a different context, the Chatam Sofer (Y.D. 338) argues that halacha takes no cognizance of events that occur only once in a thousand years (although from the historical context of the responsum it seems that he used the phrase as hyperbole). Even assuming a more robust calculation of the risk involved in performing metzitza b'peh, while it may occur more than once in a thousand years, it likely comes in beneath the halachic risk-threshold.
d. General Limitations and Localized Application
There is a trend among poskim, starting with the early medieval commentators, of reluctance to apply shomer peta'im Hashem broadly. The Terumat ha-Deshen (211) very reluctantly permits behavior that the Rabbis had labeled as “dangerous” but was practiced anyway, without apparent harm. Some scholars were marrying women who had already been widowed twice previously (a katlanit), although Rambam had ruled (Issurei Bi’ah 21:31) that such marriage is to be avoided (forbidden) due to some assumed danger. Despite the lack of statistical risk availability for this type of danger, the Terumat ha-Deshen frowned upon this practice and was uncomfortable in invoking shomer peta'im Hashem. He begrudgingly approved of the practice because otherwise these women could never marry again (mishum iguna) and he was worried that these non-marriable women might succumb to “undesirable lifestyles” (tarbut ra’ah).
I. Relying on Miracles
Similarly, the Maharil (cited above) argued against using water left exposed overnight at the start of tekufat Nissan to bake matzot. While the Mordechai and Rokeach held that such water may be used because shomer mitzvah lo yeda davar ra, the Maharil preferred the common practice of avoiding this situation by sealing the water in metal containers, insisting that “we do not rely upon miracles.” Although here too there is no calculation of risk probabilities, the choice of the term nes, would make it seem that there was some level of observable danger in drinking such water. Perhaps Maharil felt that relying on divine protection was not warranted when such situations could easily be avoided.
II. Requisite “Counterweights”
Other later poskim were similarly disinclined from liberally applying the notion of shomer peta'im Hashem and explain each instance of Chazal’s usage of this idea rather conservatively. The Divrei Yatziv (Y.D. 31) explains that we may rely upon shomer peta'im Hashem only when there is a rather compelling reason/counterweight to permit or even require the action in question, such as the mitzvah of milah be-zemanah (in its appropriate time) despite the danger perceived in doing so on a cloudy day. Similarly, Chazal relied upon shomer peta'im Hashem in allowing the three women of Yevamot 12b to have normal relations because of the dual ‘counterweight’ of the mitzvah of onah (marital relations) and the fear of hashchatat zera (wasting of seed). However, absent any compelling reason to do so, he is reluctant to apply shomer peta'im Hashem without adequate precedent.
III. Danger Stemming from the Mitzvah Itself
The Beit She’arim (Y.D. 320) goes to great lengths to further limit the application of shomer peta'im Hashem even in his understanding of Chazal’s usage of the idea. He explains that one may not rely on such ideas when the risk of danger is constant and always present, since protection from such danger would qualify as a miracle and the Gemara (Pesachim 50b) informs us that miracles are not everyday occurrences (lav kol yoma mitrachish nissa). While he does not provide proof for this explanation, it seems that he took a very literal reading of both the Gemara and Maharil’s usage of the word nes. The Beit She’arim also provides a rather novel suggestion that the idea reflected by shomer mitzvah lo yeda davar ra only applies when the mitzvah per se is the sole cause of the danger. He explains that the danger of a katlanit arises only from her marriages; a man who would have relations with such a woman without marrying her however, would be free from harm. Since the danger arises only from performing the mitzvah, one can rely upon shomer mitzvah lo yeda davar ra to protect him from this danger when his intentions are for the sake of the mitzvah.
The Beit She’arim goes on to explain the opposite case. The Shulchan Aruch (Y.D. 263:2) rules that a woman who has had two sons die from their milah should not perform a brit on her third son lest he die like his brothers. The danger is commonly assumed to be some form of hereditary blood clotting disorder and the fear is that the child will bleed to death from his milah wound. The Beit She’arim explains that even though performing a milah is a mitzvah, there is no divine protection afforded since the danger does not result from the mitzvah per se. The same level of risk would exist if a non-Jew were to perform the circumcision and thereby not fulfill any mitzvah. Even though the cause of the danger is the performance of the mitzvah (without any circumcision there is surely no risk at all) the existence of the danger does not stem solely from the mitzvah performance (ma’aseh ha-mitzvah) and therefore one cannot rely on shomer mitzvah lo yeda davar ra.
While this is a rather novel approach, it seems likely to be a post facto explanation for the application of shomer mitzvah lo yeda davar ra in a few limited instances. It does not explain why R. Papa invoked shomer peta'im Hashem to allow performing milah on cloudy days when the risk inherent in the weather does not seem to be dependent on whether or not one fulfilled the mitzvah of milah with this specific circumcision. It also does not explain why Chazal relied upon divine protection in prohibiting the three women of Yevamot 12b from using a moch during marital relations. The Gemara details the dangers that would befall these women (death to themselves, their fetus or their newborn child) and none of them seem to be dependent on whether or not the mitzvah of onah is fulfilled during marital relations. While not addressing this point directly, R. Menashe Klein explains that his grandfather meant to distinguish between the concepts of shomer mitzvah lo yeda davar ra and shomer peta'im Hashem.55 He claims that the former applies only and provides protection from those dangers that result from divine intervention in this world and not natural occurances (derech ha-teva). From the previous discussion it would seem that this protection is further limited to dangers that arise from mitzvah performance per se. When the danger is natural consideration however, one may rely on shomer peta'im Hashem when the danger is not prevalent (lo shechiach hezeika). One could therefore argue that the Beit She’arim (320) meant to discuss only the halacha of shomer mitzvah lo yeda davar ra and did not mean to address shomer peta'im Hashem at all in that responsum. Therefore, he would say that whatever the principle of shomer mitzvah lo yeda davar ra leaves out, shomer peta'im Hashem picks up the slack. While he claims that this in fact what his grandfather held, it makes much of the Beit She’arim’s discussion merely theoretical if all of the cases excluded from shomer mitzvah lo yeda davar ra are included in shomer peta'im Hashem. This makes the Beit She’arim’s nuanced distinctions entirely unnecessary and does not seem to be a very plausible reading of the text of the responsum. It does however, provide answers to the rather fundamental challenges posed above.
IV. Unique Characteristics of Milah
When dealing with milah however, there might be more reason to be stringent when it comes to accepting risks. The Rambam (Milah 1:18) lists various conditions that require delaying performing the milah past the eighth day and concludes that “We only perform milah on a child who is free from illness, since [even] questionable risks to life override all [mitzvot]; we can perform the milah at a later time but we cannot return one [lost] Jewish soul.”
Based on the Rambam’s ruling, the Chatam Sofer (Y.D. 245) suggests that a potential risk can delay a milah only when the milah could be performed in the future, presumably when the risk will be alleviated or sufficiently mitigated. However, if the potential risk were consistently present throughout one’s lifetime, one could not delay the milah on account of that risk, since doing so will insure that the milah will never be performed. The Chatam Sofer bases this upon the various reasons provided by the Gemara as to why risks of danger override mitzvah performance, but it remains —
55 Shu”t Mishneh Halachot (4:190, 15:70, 81). The authors were unable to find a responsum directly addressing this point in the Beit She’arim. somewhat ambiguous whether or not he accepts this idea as final. If this logic is accepted however, it would seem to apply to the situation of metzitza b'peh quite well since there is ample reason to assume that the rate of asymptomatic carriage of HSV-1 will not change in the near future and therefore, the possible inherent risk would be consistently present throughout one’s life. It would stand to reason that according to this view, there is no reason not to perform metzitza b'peh. Even if the Chatam Sofer would conclude differently however, it would appear that the statement of Rambam should have little to no bearing on the issue as discussed above.
e. The Nature of the Risks in Question and Possible Applications
While the reductionist trend does appear among poskim, many are willing to at times rely upon shomer peta'im Hashem. It is important to note that the Gemara applies shomer peta'im Hashem to a variety of different cases, including several that involve a direct risk to life. While the Gemara does not detail the harm that may befall a baby circumcised on a cloudy day, it does specifically mention the different risks of death to each of the three women of Yevamot 12b arising from a possible future pregnancy. It would seem therefore, that the level of risk is decisive in determining the application of the principle, not the consequences of the danger being avoided.
I. From Where does the Danger Stem?
Some poskim address the nature of dangers directly. The Beit She’arim (ibid.) explains that one may only rely upon shomer mitzvah lo yeda davar ra when the danger is not part of the natural world (eino be-teva). Because this unique divine protection of shomer mitzvah lo yeda davar ra is itself outside the boundaries of the natural world, it may only be relied upon when the danger is similarly beyond the scope of nature. This seems to include dangers that do not have an obvious casual relationship with the action from which they arise. When the risk of danger however, ‘seems’ to be ‘entirely’ natural, such as the myriad cases of pikuach nefesh, one may not rely upon divine protection and must not participate in the action in question. Practically, it seems rather difficult to determine how to apply these two categories and is instructive to see the examples cited. The Beit She’arim claims that the danger inherent in marrying a katlanit is beyond nature and as such, poskim are willing to rely upon shomer mitzvah lo yeda davar ra in permitting such marriages. The danger that circumsicion may pose to a child whose two brothers had died as a result of theirs, is within the scope of the natural world and therefore, the circumsicion is not performed since there is no room for reliance upon shomer mitzvah lo yeda davar ra. This seems difficult, since the danger posed to the three women of Yevamot 12b seems to be well within the scope of nature, and the Gemara, at least according to Rashi, requires reliance upon shomer peta'im Hashem. The simplest answer would be to argue as above that the Beit She’arim incorporated natural events within the rubric of shomer peta'im Hashem and not shomer mitzvah lo yeda davar ra, but this answer is frought with the same difficulties noted above.
R. Menashe Klein adopts his grandfather’s approach and provides examples of dangers that fit into each of these two categories that may shed light onto how to classify the possible risks inherent in performing metzitza b'peh. The Shulchan Aruch (O.C. 433:7) writes that a person is exempt from checking for chametz in a hole shared with his non-Jewish neighbor, since the neighbor may become enraged from mistakenly thinking that the Jew is performing some sort of witchcraft against him and the matter may come to great danger. Shortly thereafter, the Shulchan Aruch (O.C. 433:8) writes that a person is not required to check for chametz under a collapsed wall that previously housed chametz for fear of scorpions amongst the rubble. The Gemara (Pesachim 8a) explains that there really is no fear of scorpions during the act of bedikat chametz since the person is in the midst of mitzvah performance and sheluchei mitzvah einam nizokim. Rather, the fear is that perhaps during the bedikah the person may drop a needle into the rubble and after having completed the bedikah may return to retrieve that needle. Since the mitzvah is completed, there is no longer any special divine protection and the risk of scorpions abounds.
Many of the poskim wonder why in this latter case (433:8), if not for the external concern about the needle, was there a willingness to rely upon sheluchei mitzvah einam nizokim, but in the former case (433:7) of a hole shared with a non-Jewish neighbor, was there no attempt to rely upon this principle? R. Menashe Klein applies his grandfather’s distinction to understand the difference between the cases. He explains that the danger posed by the non- Jewish neighbor is within the scope of the natural world, while the danger posed by scorpions is not (lo al pi derech ha-teva). Therefore, one may only apply shomer mitzvah lo yeda davar ra to the latter, and not the former case. One may have previously assumed that the danger presented by the scorpion should fall within the realm of the natural world. Placing such a danger outside of the natural framework, makes it very difficult to systematically group other types of danger. While the possible danger inherent in metzitza b'peh is initiated by a person’s actions, there is certainly no attempt to harm and not even any active knowledge that one is causing any harm at the time. It would be interesting to see whether R. Klein thinks that metzitza b'peh is more similar to the danger presented by the non-Jewish neighbor or by the scorpion beneath the rubble.
II. ‘Naturally’ Encountered Risks
R. Moshe Feinstein provides some guidelines as to different types of danger and how they relate to shomer peta'im Hashem. In discussing which types of women may not use contraceptives, he explains that there is more room to be lenient for a woman for whom pregnancy may be life threatening. Reliance on shomer peta'im Hashem (and therefore strictly prohibiting contraceptive use) is legitimate for dangers that are “natural” for all women to experience, such as childbirth itself, when offset by an appropriate counterweight, such as mitzvah performance. He explains that this is not reliance upon miracles since the danger is minimally and equally present for all women. Chazal (Yevamot 12b as per Rashi and Shulchan Aruch as per Chidda [n. 37] as understood by Torat Chesed) prohibited the use of contraceptives despite the rare unfortunate cases of tragedy. R. Feinstein uses the term “naturally” to denote a status equal for all - actions that present risks of this stature may be performed, when properly offset, relying upon shomer peta'im Hashem.
It would be interesting to see how the poskim understand the possible risk inherent in metzitza b'peh in light of R. Feinstein’s distinction. If we are to assume that the prevalence of subclinical shedding of HSV-1 by asymptomatic carriers hovers around 6070%, then one might argue that the possible risk posed by performing metzitza b'peh applies to all infants equally and can therefore be dispensed with by relying upon shomer peta'im Hashem. If some specific child would have a unique condition that would make him unusually sensitive to HSV-1 transmission, this would parallel the risk of pregnancy in a women for whom it is lethally contraindicated - in both cases, R. Feinstein would not permit reliance upon shomer petaim Hashem. Practically, one may suggest that a mohel who has a bleeding mouth sore would fit into this category and as such should not perform metzitza b'peh, while all other healthy mohalim may continue the practice.
III. Normal Societal Practices
R. Elchanan Wasserman also distinguishes between the natures of different risks and posits that shomer peta'im Hashem applies only to those dangers that are not within the person’s control. However, when a person can protect himself from the danger but chooses not to - he is liable for his own tragedy. R. Wasserman clearly does not mean this to be taken literally, because in all of the cases cited by the Gemara, the risk could have been avoided by abstaining from the action, but nonetheless the Gemara relies upon shomer peta'im Hashem. He therefore goes on to explain that a person need not abstain from acting in accordance with “normal” societal practices and actions (ein ha-adam chayyav lehimana mi- minhag derech eretz). Therefore, dangers that arise from such actions are categorized as those that are beyond his control and not within his capacity to protect himself from; in such cases, reliance upon shomer peta'im Hashem is appropriate. Understood in this way, both R. Wasserman and R. Feinstein differentiate between that which is normal and common and that which is deviant, although they couch these distinctions in different terms. In R. Wasserman’s view, the poskim will have to decide whether or not the practice of metzitza b'peh is within the realm of “normal societal practices” (mi-minhagei derech eretz) or is considered something beyond normal events that a person is obligated to protect himself from. In theory, R. Feinstein and R. Wasserman disagree as to whether the risk to all people involved must be equal or that the manner in which people actually perform this action must be equal. Practically, however, the approaches seem very similar - if metzitza b'peh is considered to be the normal practice, then by extension, the possible danger inherent in its performance is posed equally to all infants and shomer peta'im Hashem can be invoked and relied upon.
IV. Modern Application
Perhaps the most revealing approach to this question is a story recounted by R. Romi Cohen when he performed milah on R. Moshe Feinstein’s great-grandson approximately two weeks before R. Feinstein’s passing in 1986. He recounts that after the milah, R. Feinstein was asked whether it was advisable to continue the practice of metzitza b'peh in light of the rampant AIDS epidemic, for fear of the child infecting the mohel. It must be stressed that in 1986 very little was known about HIV transmission, let alone therapeutics, and the fear of transmission was very real and very scary. R. Moshe replied emphatically, “Heaven forbid that [metzitza b'peh] should be abolished, since shomer mitzvah lo yeda davar ra!” R. Cohen describes the astonishment of all those present to this unequivocal proclamation and reports that several people tried to press R. Moshe on the very real danger that could come from this decision. R. Moshe simply repeated “shomer mitzvah lo yeda davar ra”. R. Cohen relates that R. Reuven Feinstein continued to press R. Moshe on the point that R. Moshe had elsewhere decided that metzitza is not an inherent part of the mitzvah of milah but rather only a minhag and therefore should not be continued in the face of possible danger.64 R. Moshe responded, “Heaven forbid changing a holy minhag that Jews practice, and this too is encompassed within shomer mitzvah lo yeda davar ra”. He qualified this by stating that in the rare instance of a specific reason to worry about the risk of AIDS, only then is it forbidden to perform metzitza b'peh. With the understanding of R. Feinstein’s previously cited formal responsa in mind, this rather powerful anecdote is merely an application of R. Feinstein’s systematic approach to shomer peta'im Hashem. It would stand to reason that R. Feinstein would feel the same way today regarding the potential risk of HSV-1 infection.
f. To Whom Does “Shomer Peta'im Hashem” Apply?
Many of the poskim cited previously required some element of counterbalance when taking upon one’s self any level of risk - be it, that such actions are simply understood as natural and everyday occurrences, or be they elements of a mitzvah. When it comes to the latter, it is important to analyze who is performing the mitzvah and who is obligated in its performance.
I. Milah of a Child whose Brothers Died from their Milah
The Beit She’arim (ibid.) explains that shomer mitzvah lo yeda davar ra does not allow [require] performing milah on a child whose two older brothers died from their milah, since the risk of danger is posed to the child and children are generally not obligated in mitzvot. It is the father who is obligated to perform milah on his eight day old child and it is he who performs the mitzvah.65 Whenever there is a discrepancy between the person performing the mitzvah and the person to whom the mitzvah poses a danger, the Beit She’arim posits that we may not apply shomer mitzvah lo yeda davar ra. However, it is important to remember that R. Menashe Klein argues that despite the limitations that the Beit She’arim incorporated in the application of shomer mitzvah lo yeda —
64 See Shu”t Iggerot Moshe Y.D. (1:223).
65 Shulchan Aruch Y.D. (260:1).
davar ra, he nonetheless believed in an expansive definition of shomer peta'im Hashem and this case may be possibly covered by the latter principle. Presumably however, since this child’s brothers died from their milah, there is some element of chazakah, that something may go wrong with this child’s milah and therefore the danger is considered shechiach hezeika (where harm is common) and not covered by shomer peta'im Hashem.
II. The Participants in the Mitzvah of Milah
Aside from the previous case of shechiach hezeika, it seems that shomer peta'im Hashem should apply in the case of a milah of a [genetically] healthy child. While the mitzvah per se is incumbent on the father, the child is integral to the mitzvah; the father cannot perform the mitzvah without him. The Avnei Nezer (Y.D. 321) seems to assume this position in discussing delaying the milah of a child with some leg deformity, when physicians state that therapeutic surgery must be done immediately and cannot wait until after the eighth day. After the surgery the child would be considered a choleh and his milah delayed until he recovers completely. While he decides that it is proper to delay the milah in this case, he analyzes the question in terms of how much suffering and/or risk a person must endure for the sake of performing a mitzvah. In the end he believes that the risk of a permanent ambulatory disability overrides the mitzvah of performing the milah bi-zemanah, at its proper time. Nonetheless, the question he poses relates to the baby himself - how much risk must the baby endure, despite the fact that the mitzvah of milah is incumbent upon the baby’s father.
The Rogachover Gaon (Tzofnat Pa’aneach 152) presents a very complex view of the different aspects of milah where he explains that metzitza is really part of the child’s mitzvah that he is to fulfill when he becomes of age, but we assume that he would allow his father to perform that mitzvah for him during his milah. Even though the mitzvah of milah is incumbent upon the father and not the child, since any risk to the child delays the mitzvah (since he is not obligated in its performance) - practically, it is equivalent to saying that the father’s mitzvah is dependent upon the child’s acceptance of risk. While indeed, these are two separate halachic actors (the father is obligated and the child is not) - they are intrinsically bound together. Therefore, both the Avnei Nezer and the Rogachover consider the mitzvah of milah to be considered somewhat ‘belonging’ to the child, at least enough to apply the dictum of shomer mitzvah lo yeda davar ra.
III. Applying “Shomer Peta'im Hashem”
While the concept of shomer mitzvah lo yeda davar ra depends on the concomitant obligation and risk of performing a specific mitzvah, the poskim do not always require such a vigorous ‘counter balance’ to the application of shomer peta'im Hashem as mentioned previously. It is appropriate to refer to the Torat Chesed’s (ibid.) understanding of the two different schools of thought regarding the nature of this principle - whether the risk is ignored because it is considered miniscule (Ritva) or because it is no longer considered to be halachically existent (Rashi). If we are to assume Rashi’s position (and indeed the Chidda showed that this was the position of the Shulchan Aruch), then it would appear that shomer peta'im Hashem applies to the possible risk incurred by the baby during metzitza b'peh. If the risk is no longer considered existent, then even if we assume that one person’s mitzvah obligation cannot override an unobligated person’s risk of danger - the father may nonetheless perform the milah despite the possible risk, since it is no longer considered meaningfully existent. It would appear therefore, that many of the poskim that still require [optimally] performance of metzitza specifically by oral suction, believe that any possible risk is below the halachically meaningful ‘risk-threshold’ - rendering such a potential risk as halachically non-existent and invoking the principle of shomer peta'im Hashem.
The Gemara (Shabbat 133b) declares that a mohel who neglects to perform metzitza puts the child at risk and ‘we’ depose the mohel from his position. As mentioned previously, poskim disagree as to the purpose of metzitza and within both camps, there are various opinions as to the nature of the danger of neglecting metzitza. a. What is the Danger that Metzitza Attempts to Alleviate?
Throughout history, poskim have understood that after milah the baby is in some type of danger and that performing metzitza [properly] alleviates this risk. Many have argued that metzitza comes to solve a medical or physiological problem - with various opinions attempting to identify the specific risk. Many of these opinions seem to reflect the ‘contemporary’ understanding of medicine of their respective generations.
I. Historical Medical Opinions
The Rambam (Milah 2:2) requires that the metzitza be of sufficient strength to draw blood from ‘the distant locations’ (ha- mekomot ha-rechokim) but does not give a more accurate description of his requirement. From a modern medical perspective, one could speculate that since sterilization was not possible, the purpose of metzitza was to remove any bacteria that may have accumulated on the wound during the milah. This would also explain why the Gemara (Shabbat 129a) views the third day after milah as the most ‘dangerous’ - despite metzitza’s best efforts, a bacterial infection, takes on average, three days to establish a systemic disease. The Tiferet Yisrael (Shabbat 19, Yachin 1) cites the ‘current’ medical opinion that metzitza is meant to prevent swelling of the surrounding areas, while others mention the risk of inflammation if metzitza is not performed properly.
II. Current Medical Opinion
Medical science today however, does not recognize any medical benefit to performing any sort of metzitza, let alone metzitza b'peh. Consequently, doctors who circumcise infants in hospitals do not apply any suction upon completing the incision; vacuum suction actually delays hemostasis, or the cessation of bleeding. While it is useful to clean the area of clots, ultimately in order to promote optimal healing conditions, direct pressure to occlude the source of bleeding and cleaning of the area with gauze is usually sufficient. Much of the scientific literature from the late nineteenth and early twentieth century adduced to defend the practice is no longer considered valid and is not relied upon medically. Therefore, according to those who view metzitza solely as preventive medicine, there seems to be little reason from a medical point of view to continue its practice today. For those who see two roles for metzitza, with elements of both mitzvah and prevention, it seems appropriate to continue the practice because of the ritual aspects.
The question about metzitza arises only when the procedure itself may pose a danger, as is contended by some today. It would seem that according to the first view, the two medical risks should be weighed against each other - the risk of not performing metzitza vs. the risk of performing metzitza and take the route of least risk. For those poskim who see some element of mitzvah as well in the act of metzitza, the discussion of section B above is vitally important in deciding what risks may, or must be accepted in performing mitzvot.
III. Other Types of Risks
Other poskim cite different types of dangers that metzitza protects against - mostly non-medical risks. There are several mystical/kabbalistic descriptions of the risks that metzitza alleviates with various explanations for the mechanism of this protective measure. These poskim understand that the Gemara (Shabbat 133b) means to say that although performing metzitza prevents only some supernatural or otherwise non-medical danger, it is nonetheless so important that we depose of any mohel who neglects the practice. According to this view, it is impossible to weigh the risks of performance vs. non-performance against each other since the latter are supernatural and hence non-quantifiable. This equation would seemingly depend on how these poskim understand the reasons for metzitza. If seen solely as a function of preventive medicine, it would appear that the possible medical risk of performing metzitza would outweigh the mystically derived risk of non-performance. However, for those who view metzitza as more than just preventive medicine, the equation is more complex as alluded to above.
b. The Weighing of Risks
R. Kook disagrees with these conclusions in one of his classic responsa dealing with medical science. He argues that science and especially medical science cannot make absolute claims about health. It is a continuously changing field, with “one generation destroying what the previous had built.” He claims that by its very nature, medical science can at best only provide its current assumption for certain causes and effects and does not even view itself as the final arbiter of truth. Nonetheless, we rely on the best medical knowledge of our time when required to violate Shabbat or Yom Tov, since even a case of doubtful risk warrants violation of these commandments. However, in other areas of halacha, R. Kook claims that there is no solid proof that medical evidence can cause the abrogation of any Torah ordained mitzvah. His understanding is even more apparent today as we witness the most rapid progress of medical sciences in history. Harrison’s Principles of Internal Medicine, often considered the “bible of internal medicine", begins with a Notice: “Medicine is an ever-changing science... [the] information. is complete and generally in accord with the standards accepted at the time of publication. However, in view of. changes in medical science. neither the editors nor contributors. of this work warrants that the information contained herein is in every respect accurate or complete.” This “notice” forms the basis of modern medical education. Therapies that were thought to be beneficial are now understood to be harmful and surgeries that were routinely performed are now shunned for their recently discovered potential harm.
I. How to Weigh Potential Dangers
R. Kook argues that since the Torah can and does provide absolutes, when Chazal declared that neglecting to perform metzitza poses a risk to a child - they ‘knew’ this to be absolutely true. In terms of halacha, this type of danger is considered a certain risk (vadai sakkana), while medical risks are halachically defined as posing only possible risks (safek sakkana). Therefore, any possible risk posed by metzitza cannot be assumed to be ‘more dangerous’ than non-performance unless proven otherwise. Since the majority of the poskim cited throughout understand metzitza to have both ritual and preventive medical elements and the possible risk of HSV transmission is far from proven - according to R. Kook’s logic it would seem appropriate to continue the standard practice of metzitza b'peh.
II. Understanding Medicine
The previous discussion assumes that any risk discussed by the Gemara must be taken very seriously and heeded to even in spite of contradictory medical opinion. The basic understanding is that since Torah is eternal, its dicta cannot be subject to contradiction by medical opinion, which by its very nature is transitory and nonabsolutist. Such logic would be very cogent for the Maharam Schik and R. Yehudah Assad cited previously who believe that metzitza b'peh derives from a halacha le-Moshe mi-Sinai. The same conclusion may not hold true for risks and precepts established by the rabbis. Authorities as early as R. Shereira Ga’on already claimed that the sages of the Talmud were indeed just that, sages and not physicians and therefore, one should not employ their suggested medical therapies. Many poskim however, do take many of these Talmudic proclamations at face value and an even greater number adopt R. Kook’s understanding of medical science and apply it practically in their halachic decisions. R. Kook’s analysis is not without precedent as the Chatam Sofer, who preceded R. Kook by many years similarly explained that medical science is an empirical study and therefore can only establish theoretical, possible doubts (sfek sefeikot) but never anything absolute. This understanding has formed the basic assumption about the practice of medicine in much of the current halachic-medical discussions. R. Ovadiah Yosef, R. Eliezer Yehudah Waldenberg and R. Yitzchak
Ya’akov Weiss all adopt R. Kook’s understanding of medical science and elaborate on it, issuing their pesakim accordingly.
III. Non-medical Risks Expressed by the Gemara
Aside from adopting R. Kook’s approach, many poskim understand many of the Talmudic discussions of specific dangers to be applicable in our times. Such an approach is not necessarily at odds with R. Shereira Ga’on’s understanding, since frequently the reasons behind these dangers remains hidden. Therefore, one cannot assume that these dangers are necessarily medically understood and as such be dismissed based on R. Shereira Ga’on’s dictum. Rather, there are many examples of these pronouncements that are taken quite literally by current poskim and require abstaining from such activities even today.
1. The Gemara (Shabbat 129a) states that a woman who has just given birth is considered to be a cholah she-yesh bah sakkana for first 72 hours post-partum. As such, Shabbat restrictions are set aside and she is exempt from fasting on Yom Kippur. R. Ovadiah Yosef (ibid.) writes that despite a physician’s opinion that such a woman is healthy enough to fast and the fast will not harm her or the baby in any way - she is still forbidden from fasting since Chazal already decided that she is in a state of sakkana.
2. When a baby suffers from jaundice, the halacha (Y.D. 263:1) requires that the milah be postponed; the length of postponement depends on the type of jaundice present. In addition, many mohalim have a tradition (mesorah) as to postponing a milah based on the shade of the baby’s skin. R. Yitzchak Weiss (ibid.) explains that even if expert physicians claim that there is no risk in circumcising such an infant, it is still forbidden to do so, since the halacha categorically considers such a child to be in a state of sakkana.
3. In defining how one ascertains whether or not some danger requires the violation of Shabbat regulations, the Shulchan Aruch (O.C. 328:3-4) states that certain injuries always mandate a necessary violation - such as injuries to the back (dorsal surface) of the hand or foot, as well as a disease known as tzafdina, a certain type of tooth disease. While doctors may decide that any such injuries are in fact non-threatening, the Pri Megadim (O.C. MZ 328:2) and Bach (O.C. 328:2) explain that since Chazal declared such dangers as sakkanot, Shabbat violations are still appropriate. The Tzitz Eliezer (ibid.) expands upon this principle and expands it to several other specific maladies mentioned by Chazal, which in spite of current medical opinion to the contrary, still permit Shabbat violations.
IV. Possible Applications
Assuming the poskim understand and take seriously Chazal’s concern for the danger of not performing metzitza - there is legitimate concern for performing it accurately and correctly. While there is a possible medical risk of danger to the infant through this procedure, these poskim nonetheless view the process as definitely halachically therapeutic. In our case, the therapy that halacha demands poses a dilemma: action entails a potential medical risk whereas inaction would result in a definite risk. This discussion therefore should then relate to how halacha views using a potentially risky therapy (safek sakkana) to treat a more dangerous (vaday sakkana as per R. Kook) underlying condition. Such a discussion is beyond the scope of this paper, but see Nishmat Avraham 2 (155:2) for a thorough analysis and review of applications of this topic.
The halacha demands that a person extend great effort in performing its precepts - possibly laying out large sums of money and undergoing personal hardships. These demands include accepting certain levels of risk as outlined above, relying on the framework of shomer peta'im Hashem. We hope that this article has provided a proper framework for assessing how the potential risks involved with metzitza b'peh fit into the general understanding of risk-taking in halacha as a starting point for further discussion.
Source: ASSIA - Jewish Medical Ethics,
Vol. VI, No. 1, December 2007, pp. 26-48
 There are no documented cases of HIV transmission through saliva (assuming that the mohel does not have a bleeding oral lesion). The risk of transmitting HIV through the digestive tract are reported to be quite minimal - especially when considering the fact that the blood is diluted in wine and then immediately expelled.
 See R. Y. B. Goldberger (Brit Kerutah li-Sefatayim (Brooklyn, NY: 1990), 104) however, where he cites the Tzofnat Pa’aneach and R. Moshe Mordechai Epstein (rosh yeshivah of Slobodka) who in fact believe that without metzitza, the circumcision is invalid.
 Chiddushei ha-Ran, Shabbat 132b.
 Techniques for performing metzitza without the mouth include using cotton wool or gauze with or without wine, using a vacuum-like device, or most commonly, using a wide tube or inverted syringe that can form an airtight seal against the baby’s skin.
 In 1888 the Orthodox Jewish community of Frankfurt issued a statement allowing metzitza using a glass tube. This statement was signed by R. S. R. Hirsch (Shu”t Shemesh Marpeh 55) and agreed to by Rabbi Yitzchak Elchanan Spector and Rabbi E. Hildesheimer. R. Chayim Ozer Grodzinski, R. Kook and others have also written response allowing for use of the glass tube and it is frequently quoted that R. Chayim Soloveitchik insisted on using a tube as well. Recently, the Rabbinical Council of America issued a statement saying that “the normative halacha undoubtedly permits [suction generated by the mouth using a tube] ... and that it is proper for mohalim to conduct themselves in this way given the health issues involved [with metzitza b'peh].” For a listing of these and other sources, see Sefer ha- Brit in the addendum on p. 222.
 However, please see the position of R. Moshe Feinstein related in section B (e) below.
 Following an attack on the practice throughout the 19th century, a fierce debate erupted and continues to this very day regarding the necessity of direct oral contact. The Sedei Chemed (vol. 8 Kuntres ha-Metzitza) cites a proclamation signed by over 42 rabbis proclaiming that metzitza may only be performed by direct oral contact and not via a tube. Closer to our times, after the outbreak of the AIDS epidemic, a similar proclamation was signed by many of the gedolim of America, Israel and worldwide prohibiting the use of a tube (Brit Kerutah li-Sefatayim, 108). It is important to note, that contrary to popular assumption, many of the signatories are not of Hassidic background (i.e., R. Avrohom Pam, R. Elya Svei, R. Mordechai Gifter and R. Shlomo Zalman Auerbach). While it is abundantly clear that the historical circumstances surrounding the original controversies were far different than the current reality, this article will not address that complex area and the halachic conclusions arrived at will be taken at their face value.
 Also see Shu”t Yehudah Ya’aleh (Assad) Y.D. 1:248.
 The Rambam (Milah 2:2) states that metzitza is meant to suction blood from ha- mekomot ha-rechokim (the distant places), and while he does not explain further, these poskim understand that the mohel must create a vacuum around the wound to accomplish this task.
 Based on Pesachim 57b, relaying the story that a cry [among others] was heard in the azarah: “Take out Yisachar Ish Kefar Barkai, who honors himself and disgraces the kodshim’ as he would wrap silk on his hands and perform the service (avoda).” Rashi (s.v. karich yadei) explains that wearing gloves creates a chatzitza (separation between the shochet and the animal) and is also a bizayon ha-mitzvah. It is beyond the scope of this article to analyze the scope of bizuy ha-mitzvah. For further analysis see Pitchei Teshuvah (Y.D. 271:19), Birkei Yosef (Y.D. 271) and Iggerot Moshe (Y.D. 2:16).
 See Shu”t Yabbia Omer (O.C. 2:25:14; Y.D. 2:20:4; E.H. 2:7:3; Y.D. 3:13:6; O.C. 4:2:11; O.C. 7:7:3).
 See Yalkut Yosef (Issur ve-Heter 1, 6) and Iggerot Moshe (Y.D. 2:16) who explain that the Gemara in Pesachim does not refer to a person who wears gloves as a means of hygienic protection.
 The writers have indeed confirmed this last point with several mohalim. One was confident that by using a tube he created an airtight vacuum at least 95% of the time while another was confident 100% of the time.
 The frequency ranges from once per month to twice per year in infected individuals. Klein R, “Epidemiology of herpes simplex virus type 1 infection", www.uptodate.com; The Red Book, American Academy of Pediatrics report of the committee on Infectious Disease, 25th edition, 309-319
 These symptoms include oral or perioral lesions, ocular infections, non-genital skin lesions and genital skin or mucous membrane lesions.
 Whitley R, “Predictors of morbidity and mortality in neonates with herpes simplex virus infections", The NIAAD Collaborative Antiviral Study Group, New England Journal of Medicine 324 (1991):450-4.
 Committee on Fetus and Newborn, Committee on Infectious Diseases, “Perinatal Herpes Simplex Virus Infection", Pediatrics 66 (1980):1.
 High dose Acyclovir therapy was associated with a trend toward an increased likelihood of the infant being developmentally normal at 12 months of age. However, less than 30 percent of patients were developmentally normal and approximately 60 percent had moderate to severe disability (Kimberlin DW, “Safety and efficacy of high-dose intravenous acyclovir in the management of neonatal herpes simplex virus infections", Pediatrics 108(2001):230-8.
 Corey L, “Infections with herpes simplex viruses", New England Journal of Medicine 314 (1986):686.
 Scott DA, “Oral shedding of herpes simplex virus type 1: a review", Journal of Oral Pathology & Medicine 26 (1997):441-7.
Schillinger JA, “National seroprevalence and trends in herpes simplex virus
in the United States, 1976-1994", Sexual Transmission of Disease, 12 (2004):753-60.
 Also noteworthy was that the prevalence increased with age in both genders. Davidovici BB, “Seroprevalence of herpes simplex virus 1 and 2 and correlates of infection in Israel", Journal of Infection (2005):1-7.
 Slacks SL, “HSV Shedding", Antiviral Research 63 (2004):S19-26.
 Rubin LG, “Cutaneous neonatal herpes simplex infection associated with ritual circumcision", Journal of Pediatric Infectious Disease 19 (2000):266-8; Distel R, “Primary genital herpes simplex infection associated with Jewish ritual circumcision", Journal of the Israel Medical Association 5 (2003):893-4; Gesundheit B, et al, “Neonatal genital herpes simplex virus type 1 infection after Jewish ritual circumcision: modern medicine and religious tradition", Pediatrics 114 (2004):e259- 63.
 Since HSV is known to incorporate itself into the host genome, a DNA analysis between an asymptomatically infected mohel and an affected child could show that they are indeed one and the same strain. Such a test would greatly increase the aforementioned association, but has not been performed (or is simply not part of the public record).
 HSV remains viable for several hours on skin, cloth or on plastic. (Turner R, “Shedding and survival of herpes simplex virus from fever blisters", Pediatrics 70 (1982):547-9). HSV-1 virions have been recovered for up to 2 hours from door handles on which HSV-1 in saliva and in water had been inoculated (Bardell D, “Survival of herpes simplex virus type 1 on some frequently touched objects in the home and public buildings", Microbios. 63 (1990):145-50).
 Saliva contains factors, in addition to anti-HSV immunoglobulins, that neutralize HSV and may indirectly contribute to the control of recurrent Herpes labialis (Valimaa H, “Salivary defense factors in herpes simplex virus infection", Journal of Dental Research, 81 (2002):416-21).
 While the simple meaning of this verse refers to returning lost objects, the Gemara Sanhedrin 73a explains that this mitzvah also includes “returning” a friend’s health, when it may be at risk of being “lost.”
 It must be noted however, that the prohibition of “lo ta’amod al dam rei’echa” - loosely translated as “you shall not stand idly by while your friend’s life is in danger” - is also operative in this context. As will be explained later, more is required of a person in avoiding violating a prohibition than in performing a positive mitzvah. While this might be a rationale for the Yerushalmi’s position, the Beit Yosef does not suggest it.
 The Beit Yosef then quotes the familiar Gemara in Sandhedrin 37a that a person who saves the life of one Israelite is considered to have saved (established) the entire world, with no further comment. Perhaps this is meant as his justification of the Yerushalmi - the calculus must not be risking one’s life to save another’s from certain death, but rather risking one’s life to save the entire world. The halacha in other areas recognizes a difference between saving the life of an individual versus saving the lives of many people. See Yerushalmi Terumot (8:4) where the Gemara discusses giving up one person's life to save an entire city.
 The Radbaz seemingly assumes that by the three cardinal sins that one must give up his life to fulfill, the Torah must specifically mandate that by these sins but not others, even darchei no’am has limits.
 It is important to also see the Radbaz's other [often overlooked] responsum (5:218) where he states that a person is obligated to risk his life to save his fellow's when the risk to the rescuer is less than 50%. This responsum clearly limits the applicability of the former principle.
 See Tzitz Eliezer (12:57; 13:100) and Yabbia Omer (C.M. 9:12) and the sources cited therein. It is possible to say however, that the Radbaz did not mean to establish a general rule by all mitzvot, but rather dealt only with the specific case in front of him. Perhaps the Radbaz felt that it was a violation of darchei no’am principle to purposely not set a very dangerous precedent of Jews being threatened with sacrificing their limbs to save their fellows from imminent death. Alternatively, he felt that darchei no’am would prohibit a person from risking his life for a seemingly frivolous purpose - namely to prevent a assailant from harming another person. Perhaps however, for the constructive purpose of positively saving a friend’s life, the Radbaz may have indeed felt that such actions were permitted and perhaps required. Futhermore, see Shu”t Afarkesta de-Anya (C.M. 4:320) who argues that other poskim do not necessarily arrive at the same conclusion.
 See sources cited in Yabbia Omer Y.D. 6:13:5.
 The exemption lies in the nature of the mitzvah of sukkah. The Gemara (Sukkah 26a) explains that one must dwell in the sukkah in the same manner in which was dwells in a house (teishvu ke-ein taduru). Just as a person would not dwell in a house where he experiences discomfort, similarly he is exempt from dwelling in a sukkah in such a scenario. However, the nature of this mitzvah is different on the first night. The Gemara explains that the requirement to dwell in the sukkah on the first night is derived from a gezeirah shavah from the mitzvah of eating matzah on the first night of Pesach and not from teishvu ke-ein taduru. Therefore, there is no reason to exempt a mitzta’er on the first night of Sukkot. There is indeed a controversy regarding the source of this pain or discomfort and will be dealt with shortly.
 One of the only other places that there is an exemption for one who is mitzta’er is by tefillin. The Rema (O.C. 38:1) explains that a sick person who is mitzta’er is exempt from wearing tefillin since, as the Mishna Berurah (38:5) explains, the discomfort will prevent him from properly concentrating on the mitzvah of tefillin. This certainly seems like a local ruling regarding the specific requirement of yishuv ha-da’at by tefillin and cannot be extrapolated from here to other areas of halacha.
 The Taz (O.C. 640:8) however, believes that even where refraining from dwelling in the sukkah will not prevent an increase in tza’ar a person is nonetheless exempt from the mitzvah. He explains though that this is because of the unique requirement of sukkah of yishuv ha-da’at for the proper kavannah of dwelling in the sukkah, and therefore would seem to agree that this paradigm is valid in other areas of halacha.
 Interstingly, the debate between the Chelkat Yo’av and the Binyan Shelomoh surrounds their different readings of the Gemara’s question of Rava’s claim that a mitzta’er is exempt from sukkah. The Gemara questions Rava by claiming that the Mishna only exempted a choleh from dwelling in the sukkah but not a mitzta’er. The Gemara responds that by a choleh, even his attendants are exempt from dwelling in the sukkah, whereas the attendants of a mitzta’er are nonetheless obligated.
 Mikra’ei Kodesh Pesach 2, no. 31.
 “Im Adam Chayyav Lehachnis Atzmo le-Choli Lekayyem Mitzvat Aseh", Halacha u- Refu’ah 4, 147.
 “Be-din Choleh u-Mitzta'er be-Mitzvot", Halacha u-Refu’ah 4, 125.
 See Chazon Ovadiah: Haggadah shel Pesach No., 4 where Chacham Ovadiah Yosef extends the application of derech cheirut to other mitzvot of the seder as well, namely matzah and marror. He therefore argues that similar exemptions should apply to these mitzvot as well and one need not exert himself so much in their performance that he become bedridden.
 R. Scheinberg formulates this is a manner familiar to many from the laws of Shabbat. The Gemara in Yoma 85b attempts to find a source for the permission to violate the laws of Shabbat in saving a life by deriving from Shemot (31:16) that it is preferable for a person to violate one Shabbat so that he may [live to] fulfill the mitzvah of Shabbat in the future.
 Several specific mitzvot however, have different local parameters that govern the exertion required in their fulfillment such as sukkah and tefillin.
From the first cases discussed by the Gemara it may seem that because dashu beih rabbim, we may apply the principle of shomer peta’im Hashem. However, from this last case it seems clear that there is no requirement of dashu beih rabbim, but rather, it is only a reason to apply the principle.
 See Shu”t Yabbia Omer O.C. I (23:5) as to how this idea might be applied to matzot prepared for the latter days of the festival.
 Sefer Maharil, hilchot maya de-lishat ha-matzot,  s.v. tekufat.
 He also advises that on a cloudy Shabbat, it is proper to not perform the milah. See the comments of R. Refael Yasfan (footnote 219) in the Mossad ha-Rav Kook edition of the Ritva (72b) as to why milah on a cloudy Shabbat is only not advisable but not forbidden.
 As per Shu”t Chayyim Sha’al I (59).
 For a variant on this approach, see R. Stanley Boylan, “Chashash Sakkana le-Ohr ha-Halacha", Ohr ha-Mizrach 32 (1984):48-59.
 See also Shu”t Avnei Nezer O.C. (454), Shu”t Mishneh Halachot 15 (81).
 The Mishkenot Ya’akov (Y.D. 17) goes to great lengths to prove that mi’ut ha-matzui is defined as a 10% occurrence and R. Shlomo Zalman Auerbach is often quoted as endorsing the Mishkenot Ya’akov’s opinion (see Bedikat ha-Mazon ka-Halacha, p. 181 who quotes R. Yosef Shalom Elyashiv as well as endorsing the 10% approach). R. Hershel Schachter frequently cites R. Yosef Dov Soloveitchik’s opinion that mi’ut ha-matzui should be approximately 14.5%, based on what he determined was the actual incidence of sirchot in cow lungs in his time. See however, Shu”t Shevet ha-Levi Y.D. (4:81) who seems to adopt a more subjective approach.
 This responsum deals with the German law that required that a body be left for three days since declared dead by a physician before burial. There were apparently instances in which a person, who had been previously declared dead and subsequently buried, was later found to be calling for help from his grave. From the very fact that this legislation was deemed necessary, it seems that it was to prevent an occurrence of some noticeable frequency, certainly much greater than once in a thousand years. These types of events are the subject of the Chatam Sofer’s statistical estimate.
 The Beit She’arim was written by R. Amram Bloom, grandfather of R. Menasheh Klein, the rabbi of Ungvar and rosh yeshivah of the institution bearing the name of his grandfather’s book.
 He explains that according to the view that one may “desecrate one Shabbat so that he may keep more Shabbatot in the future” (Yoma 85b), the permission to desecrate the first Shabbat is contingent upon the ability to perform that very same mitzvah (keeping Shabbat) in the future. When the possibility to perform the specific mitzvah in question is not possible, there is no permission to violate the halacha in the first place. He notes that the Rambam himself accepts the alternate rationale of violating halacha for pikuach nefesh of “ve-chai bahem” and that according to this view, the violation of halacha in not contingent upon possible future performance. The Chatam Sofer notes however, that ‘elsewhere’ he discusses that in practice we require both of these rationales to permit mitzvah violations. He seems to discuss this issue in Shu”t Chatam Sofer O.C. (85), but does not provide a conclusive answer and explicitly mentions that that discussion is meant only theoretically. His conclusion therefore, seems somewhat ambiguous.
 Shu”t Mishneh Halachot 4 (190).
 The Mishna Berurah (433:30) explains that the non-Jew will misunderstand why the Jew is walking around with a candle at night checking locations throughout his house since the next morning, such checking could be done much more easily.
 The Magen Avraham (433:12) and others explain that in the case of the shared hole, the danger was rather prevalent (shechiach hezeika), and as mentioned previously, in such circumstances, reliance upon divine protection is inappropriate.
 Shu”t Iggerot Moshe E.H. (1:63:1-2, 4:73:1).
 Kovetz Shiurim, Ketubot no. 136.
 Brit Avraham ha-Kohen, 199-200.
 See Boffey P.M., “U.S. counters public fears AIDS", The New York Times, 20 September 1985; Levine J, “AIDS: prejudice and progress", Time Magazine, 8 September 1986; Korcok, M, “AIDS hysteria: a contagious side effect", Canadian Medical Association Journal 133 (1985):1241-8.
 This explanation is somewhat difficult however, since elsewhere, the Avnei Nezer (O.C. 444) states that specifically by milah, shomer mitzvah lo yeda davar ra can only apply to the father since it is only he who is obligated in the mitzvah. This apparent contradiction is left unresolved.
 See Kovetz Dam Brit, 1-2.
 Many of these authorities were unaware of many of the myriad infectious agents known today and therefore could not have considered their effects appropriately. R. Goldberger quotes extensively (p. 26) from Dr. Sherhai (Meishiv Nefesh) indicating the ‘current’ medical opinion of 1906 that was unaware of blood borne pathogens. Today we are aware that many pathogens live, replicate and cause infection in the blood, making Dr. Sherhai’s discussions no longer relevant but nonetheless cited by R. Goldberger as authoritative.
Commentary of the Vilna Ga’on to the Tikkunei Zohar (37) and Tikkun
18 as well as
Sha’arei Orah (sha’ar 5 in analyzing Tehillim 118) both cited by R. Goldberger, 82.
 See R. Chayyim Vital, Ta’amei ha-Mitzvot (end of parshat Lech Lecha) and R. David Lida (Sefer Sod Hashem) cited by R. Goldberger, 96.
 Shu”t Da’at Kohen (142). In responsum 140 he elaborates further and attempts to prove that medicine is always halachically viewed as only possible truth.
 Kasper, D.L., et al, Harrison’s Principles of Internal Medicine, 16th ed. (New York: McGraw-Hill, 2005), vi.
 See also Meshech Chochmah, Bo quoting the Gra in explaining that the reasons expressed by the Sages for various laws are not exhaustive and, that for some reason, the Sages chose not to publicize other considerations.
 It is important to note that R. Kook himself however, did not see any problem with using a tube to perform metzitza and therefore recommended its use in any case of possible danger.
 Otzar ha-Ge’onim X, Gittin 68b. Such a trend is found throughout the rest of halachic history in many areas but it is beyond the scope of this article to trace this line of thinking.
 Shu”t Chatam Sofer Y.D. (175).
 Shu”t Yabbia Omer O.C. (7:53), Shu”t Tzitz Eliezer (8:15:10, 14:89) and Shu”t Minhat Yitzchak (3:145).
 See R. Joshua Flug, “Jaundice and Circumcision", JME Vol. V, No. 1 (2004), pp. 4048; reprinted in this volume pp. 65-81.