The Gemorah on 34 asks, and appears to conclude, that Ain Isha Misaberes B'Biah Rishonah (a woman cannot conceive from the first time she has relations), unless perhaps, according to Rav Nachman, she previously broke her hymen (per the answer given to explain Tamar and Yehuda).
Although I am not an expert, it appears to be assumed today that a woman could conceive from the first time she loses her virginity even if her hymen was intact.
Is this a case where we need to answer "Nishtana hatevah" (physical nature has changed) -- or that the current conventional wisdom is wrong? Is there a possible approach that Rava (who questioned Rav Nachman) disagrees with him? Do Achronim address this theorem in light of current conventional scientific thought?
Thanks for any approaches on this subject.
Avi Scheiner, Passaic, New Jersey, USA
The Noda B'Yehudah (Kama EH #22, Basra EH #31) writes that this means that the majority of women do not become pregnant from Bi'ah Rishonah. There is much discussion regarding whether or not this approach is correct (see note of Rav Tzvi Hirsch Berlin on our Gemara). This position is reinforced by the Teshuvos Shivas Tzion (#73) and Sho'el u'Meishiv (1:1:25, who answers the various questions from the Medrash which imply that it is a rule).
This is what I knew before I contacted Dr. Shaul Baruch, a known expert gynecologist. He said that scientifically, there is no less chance of a woman becoming pregnant from Bi'ah Rishonah than someone who is not a Besulah. If this information is correct, we might have to use the answer of Nishtanah ha'Teva (possibly even from the time of the Noda b'Yehudah), as you suggested.
All the best,