I've never 'fancied' a girl. I can appreciate a pretty girl...but that's about it.
I think, my personal opinion, that you have to sway slightly both ways to fancy someone of the same sex.
I have a few gay cousins, the female and the male describe the opposite sex in a similar fashion. The thought is distasteful. Bunch of hetrophobes...!!!
The point is....they find sleeping with the opposite sex as distasteful as I find sleeping with the same sex (and I'm talking about ME here...not gay couples)
You can't be made gay...imo.