What was the sin of the daughters of Lot The Rambam (Isurei Bi'ah) rules that it is not prohibited for a Ben Noach to marry his daughter!
I found an answer in the Perush Bris Olam on the Sefer Chasidim (#489). He writes that in the days of Lot, the Bnei Noach took upon themselves many Chumros with regard to prohibited relations. If so, why didn't the Rambam mention them? In addition, what is the source of the Bris Olam for this Are there any other answers?
Haqatan Aharon Braha HY"V, Milan, Italy
Unfortunately, I am currently in London and do not have access to a Hebrew computer. The question is raised in Tosfos Nazir 23a. Tosfos explains that this Gemorah is according to the opinion that a non-Jew may not be with his daughter. Tosfos adds that even according to the other opinion which permits it, nonetheless the Gentiles have chosen to refrain from such relationships.
The Rambam does not mention the additional abstentions which the Gentiles have accepted upon themselves. The Gemorah in Chulin (92a) states that the Gentiles have accepted upon themselves thirty Mitzvos, but the Rambam makes no mention of this.
Yehuda Landy