I don't know. I've always fantasized about receiving during sex, yet I'm not attracted to most men (I like women quite a bit); thinking about receiving or rape fantasies is what turns me on. The strange part is I usually fantasize that it's a man, even though I'm not all that attracted to men. I didn't realize it was weird until a little while ago and it was never conditioned in me. I also never realized being auto-erotic was weird in men.
From reading about cross-dressers, I don't think that was something they were conditioned into. They feel good doing it and try to stop, but usually feel like they are missing a part of themselves, even if they feel guilty about it.
Supposedly, prison can make some people bisexual, but they aren't bisexual when they get out of prison, so I'm not sure that counts. It sounds gross, but they take what they can get...I guess...