This is the crux of the whole issue, IMO:
'Claire believes that her feeling that she was a boy stemmed from rigid views of gender roles that she had internalized. “I think I really had it set in stone what a guy was supposed to be like and what a girl was supposed to be like. I thought that if you didn’t follow the stereotypes of a girl, you were a guy, and if you didn’t follow the stereotypes of a guy, you were a girl.”'