IVF and other fertilization techniques in Halacha

My wife and I are 47 years old. We have two boys. One of our boys is 4.5 and is experiencing some real problems with speech. Perhaps for this reason, or other reasons, we have for some time thought of trying to bring in another child. My wife has been told that we may need to do Hfraya (Hazraya) Melchutit. I am completley not well versed with the subject and would appreciate knowing whether there is any prohibitions on doing this from a religious point of view.

Thank you.