You often hear about "double standards" between men and women, such as a guy who get's lucky regularly is a stud, while a woman might be called a slut.
This is one area I think there is a bit of reverse discrimination. Traditionally, women have been more demostrative of affection to one-another, and it's no secret that guys enjoy watching/participating with two females.
But there's a much greater stigma attached for males getting together sexually.
I once read that we are all bi-sexual, our sexuality is not black and white, but shades of grey. It's what we're taught as we're raised, religious beliefs, and how well we control urges that decide whether we'll act on it or not. In fact, the article said that those of use who are most outwardly homophobic are the most likely to have a great fear of our own homosexual tendancies.
I was very homphobic as a teenager, and have become much more open minded as I've matured. While I haven't had the occasion, I wouldn't dismiss it in the right circumstances, and I sure don't hold anyone's sexual orientation against them.
About 20 years ago, I was seeing a girl and turned her on to enemas, and she loved them. She had a gay male friend, and when he heard this, he tried very hard to arrange getting together with me, or the two of us. At the time I demured, but have often wondered what that would have been like.