This is a good one.
Yesterday:
Mom: the reason why your like this is because your father wanted a boy.
Me: Well he has a boy, Three of them.
Mom: Why don't you just be a girl who dresses like a boy, and has boyfriends?
Me: Because I'm not a girl, and I'm into girls
Mom: Why don't you be a lesbian?
Me: Because as far as I know you have to be a girl to be lesbian. Which I am not.
Mom: (Furious) You just don't like girls so you hate yourself

Me: Well, they do have cooties.. Thank God I'm not a girl then, Right mom?
Mom: .....