Also I don't think environment has anything to do with it. In my opinion you're either gay or you aren't. It might for fake gays and some bis it's become society standard for many straight people to say they're bi because it's "trendy".
I don't know about this. Again, I'm of the opinion that
there is a spectrum, and no one is purely anything. I have
almost no attraction to males, but have acted on what I
have, a bit. I consider myself straight, but could easily see
becoming much more bi, under different circumstances
(say I found a male who really attracted me, or was slipped
into it, through a female who really wanted a particular triad).
I've always seen it as a matter of taste. Fat women disinterest
me a great deal more than those who are close to my taste, but
of my own gender. But, that's just me.