There is what appears at first glance to be a technical passage (although some may find it of interest on its own) in the Talmud dealing with the issue of which types of impurity bars one from Torah study. The Talmud states “הזבים והמצורעים ובעולי נדות קורין בתורה ושונין מדרש הלכות והגדות ובעלי קרי אסור בכולן” “A zav, a metzorah, boli niddot, are permitted to read from the Torah, study Midrash, Laws, and ‘agadot, however a ba’al keri can study none of these.” So according to this all these types of men, as this is in the masculine, are able to study these things even though they have some level of impurity. This is how it appears in the Talmud Bavli.

However, the Jerusalem Talmud and the Tosefta preserve a different reading. They have both men and women in the list. Hence “זבין וזבות נדות וילדות קורין בתורה וכו” “zavim and zavot (the feminine) and menstruating women, and a women who just gave birth can read from the Torah etc.” according to this reading women would need to know whether they could engage in study of Midrash and Law etc. So what happened?

Lieberman states “I think that the women would intentionally removed [from the Munich manuscript of the Talmud Bavli and hence our corrupted texts] and were replaced with men.” So the menstruating women were replaced with a man who had marital relations with a menstruating woman. And instead of a woman who gave birth we have a metzorah. The reason is obvious to have the Talmud discussing whether women in this state of impurity could study these texts assumes that they regularly studied them, something that for some may not have been accepted.

Sources: Saul Lieberman, Tosefet Rishonim vol. 1, 15; Jerusalem Talmud, Berakhot, 3:4; Talmud Bavli Berakhot 22, a; Tosefota, Berakhot 2 :12; Lieberman, Tosefta K’Peshuto p. 20.