I don't think everyone is bisexual, but then again that depends on your definition of such. I've encountered MANY girls who, drunk or not, have kissed members of the same sex, yet they insist they are straight. Maybe they were just satisfying some curiosity, or maybe they see it as purely innocent and the kiss wasn't because they were sexually attracted to the other girl. There's girls out there that would have a 3some to satisfy their boyfriend's fantasy... yet even after the fact, still say they are straight.
It seems totally acceptable (as I think it should be) for women to look at other women and appreciate their beauty. We can say "wow she has gorgeous hair/legs/breasts, etc" and we don't necessarily mean it in a sexual way. Maybe we just wish we had what she had. It doesn't seem as acceptable though, if a guy were to admire another guy's attributes (in a non-sexual way).
/shrugs
This is one of those questions/theories that will probably never have a solid and definitive answer.
Chrissie ~ shouldn't this be in SLR?