Rashi and Science

So, back to some original topics I've discussed in this space. This one has to do with a Rashi in Bereshis, 19:36. In the story, the daughters of Lot "believe," having just witnessed the destruction of Sodom and Gomorra, that the entire world has been destroyed, leaving just them and their father as the world's only survivors. So, they decide to copulate with their father and begin repopulating the planet. They get him drunk two nights in a row, and each night, one daughter sleeps with him and conceives. Says Rashi (quoting Medrash Rabbah):

And They Conceived: Although a woman does not become pregnant after one "encounter," these [women] controlled their bodies and brought out their "ervah" and conceived after only one encounter.

Nice, interesting idea, right? Well, not so much. First of all, the Shulchan Aruch tells us women had much more awareness of their bodies "back in the day." Second, this being a possible fact, is it not, pardon the pun, conceivable that these daughters of Lot did knew their bodies' cycles, knew when they would be at peak ovulation, knew how to get themselves aroused (I'm sure Lot was of no help...), in order to conceive on the first try? It's not an uncommon occurrence, after all. Could Rashi have been wrong?

Yes, he could have. Once again, while Rashi was a Torah giant, his knowledge of biology probably left a bit to be desired. Of COURSE women conceive after the first time. It's really a question of timing, not commanding one's body to something not natural to it. Now, could Rashi in some way have been correct? Certainly. When Rashi says they controlled their bodies, it probably had to do with them knowing when they were ovulating (certainly, they knew when their last period had been and knew enough to understand when the best time to conceive was) and getting aroused so things went "easier." But if Rashi was talking in euphemisms, he seemed pretty explicit in what they did, and knowing what they really did would probably have been easier and more comfortable to explain than essentially saying they turned themselves "on" and thus conceived. More likely, I think, as is often the case with Chazal, Rashi's science education was sorely lacking and this was the only way for him to explain something he simply did NOT understand. I guess what really bothered me here was Rashi's statement that a woman does not conceive after only one encounter, and that's JUST factually WRONG. So Rashi had to come up with some way to explain his puzzlement at something he did not understand (nor did the authors of the Medrash Rabbah he quoted, apparently), and this was the best he could come up with.