Reply To: Why is Jewish identity matrilineal and not patrilineal?

It’s a 3-way Machlokes Tannaim. I think we assume it’s from the Passuk in Ki Sisa, “V’hiznu Es Banecha Acharei Eloheihem”, that your kids from a Nochri male are considered yours but not from a Nochri female. (By the way, a small but significant chunk of Rishonim there hold that you need two Jewish parents for a kid to be Jewish. However, that Shittah has been completely rejected and is not even used in the Achronim for such important cases as Hataras Agunos.)