Tuesday, March 8, 2011

Rav Herzog to Rav Unterman regarding rejection of paternal blood test

Rav Yitzchok Herzog(Assia 5 page 196-197 translation by R’ Dov Frimer): I do not deny that I was almost embarrassed ... by what you wrote ... in such a deprecating manner towards blood tests, from a negative aspect. That is, with regard to the possibility that [a blood test can] clarify that X is not the son of Y. How can there be a question of the credibility of the doctors in a matter which has been clearly accepted by all the masters of medicine throughout the entire world! Our Sages nowhere say that it was a statement handed down to Moses on Sinai .... Moreover, this is impossible, since it is now as clear as the sun at high noon... . However, they .held it as a fact and built on this assumption, since Aristotle had so asserted and so had been accepted by all the scholars of his time. What vast differences there are between the science of medicine in their day and in ours, and between the contacts that exist between all parts of the world today, in contrast to the state of affairs in ancient times! I remember from my reading of medical literature that there is no doubt whatsoever concerning this matter. Yet in your letter you imply that there are differences of opinion among medical experts. With all due respect, you are completely mistaken. Here is a copy of a letter from the government’s medical-legal expert who is also an observant Jew. The husband has already come to me and asked that the judgment be executed. You do not accept this. We shall give him an extension, and I am arranging the matter here and will notify the parties through you as to when they must come. It is unfortunate that while science is progressively conquering worlds and discovering all sorts of secrets, although it too errs at times, we like ostriches bury our heads in sand. It is imperative that we encourage the ablest students of the yeshivot also to be educated as men of science in each discipline, so that we should not need to turn to others in matters of physiology, chemistry, electricity, etc. concerning things that relate to our sacred Torah. ...


  1. I can see bending over backwards not to accept the results of paternal blood tests because it is an established halachic principle we don't going looking for reasons to create mamzerim.

  2. What was the ultimate outcome of this case? I had heard that the overwhelming majority of poskim will not allow the admission of the evidence of blood tests when the result would be to make someone a mamzer. Is this changing? Was it ever true?

  3. In a nutshell, what is the point the two rabbonim are arguing?


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