levite

I think anyone who is sexually attracted to both genders is bisexual. Doesn't matter if they act on it or not.

I also think that "perfect" bisexuals (equally attracted to both genders) are rare. I tend to think that everyone prefers one sex or the other, even if it's just a smidgen more.

That said, I think most women lean at least a little toward bisexuality. Not that all women want to have sex with other women, but it seems like nearly all of the women I've talked with about sex admit that they have at least seriously considered having sex with another woman at least once. Granted that men might all just be in denial, but it seems like truly bisexual guys are few and far between. Most of the men I've spoken with were either straight, and rarely if ever even considered having sex with another man, or gay, and had always known it, even when they were in denial and in the closet. Most of the nominally bisexual men I've known ended up being gay, and had just had issues coming out. And of the couple of truly bisexual men I've met, all had a pronounced inclination (mostly like men, but occasionally get a taste for girls, etc.); whereas most of the many bisexual women I've spoken to were a lot closer to 50/50.

I think women's sexuality is just naturally a little more fluid and flexible than men's, for the most part. In part, I think that results from women often being better at handling complex choices than men: when confronted with choices, we men tend to like to pick one and stick with it.

Obviously, these are all generalizations, and won't hold true for everyone. But I think they tend to be true more often than not.

__________________
Dull sublunary lovers love,
Whose soul is sense, cannot admit
Absence, because it doth remove
That thing which elemented it.

(From "A Valediction: Forbidding Mourning" by John Donne)