Two sages — R’ Ishmael (son of Rabbi Yossi) and Rabbi Elazar (son of Rabbi Shimon) — were extremely fat and had extremely large bellies. When they stood belly to belly a yoke of oxen could pass beneath their bellies without touching their flesh. A respected gentile woman once met them and said that with bellies that big they could not possibly have full sexual relations with their wives. If so, the respected gentile lady argued, the sages’ sons are not really theirs, but were sired by other men. They answered her: Our wives have even larger bellies than we do [hinting that following her own approach, no man would be able to have sexual intercourse with them]. If so, how did they manage to actually have sexual relations with their wives? Answer: The larger the man’s body, the larger his sexual organ. Since the sages above had very large sexual organs, they could impregnate their wives. Another answer: Desire and craving can make the impossible happen and the very fat couple will manage to have sexual relations: “Love compresses the flesh.” The scholars asked: Why did the sages answer the gentile woman when her whole question was merely to annoy? Is it not said “Answer not a fool according to his folly?” Answer: If they did not respond to the words of the gentile woman it might be taken as an admission, so they answered her so their sons would not be mocked. One of the scholars, R’ Yochanan, described the large size of Rabbi Ishmael’s sexual organ thus: The size of his sexual organ is as a bottle which holds 12 liters. A different scholar, Rav Papa, described R’ Yochanan’s sexual organ: The size of his sexual organ is as a bottle which holds six liters, and some say only four liters. Later scholars described Rav Papa’s sexual organ: The size of his sexual organ is as the wicker-work baskets of Harpania.
(Babylonian Talmud, Tractate Bava Metzia 84a)