As referred to in Mean Girls, the Rules of Feminism state that no girl can date her friend's:
Ex-Boyfriends,
Crushes,
or
Relatives
Follow these simple rules and avoid hell in Girl World.
"Oh, no, you can't like Aaron Samuels.
That's Regina's ex-boyfriend. Ex-boyfriends are just off-limits to friends. I mean, that's just, like, the Rules of Feminism!" - Gretchen Weiners (Mean Girls)

by R!aaaachellll June 21, 2007
Get the Rules of Feminism mug.