I think Phantom Stranger has it right, you must look at the history of sex to truly understand what's going on. There really is no such thing as homosexuality and being gay, it's a modern term coined to define and put people in their place.
If you look at ancient societies from the Greeks to the Romans, you will see that sex was about the pentrator and the penetrated. The most powerful in society, the senators and the aristrocrats had women for pleasure and also importantly for reproduction but also had men around to penetrate, I sign of great power in the ancient world. No one thought of these senators as being "gay", people just didn't think in those terms back then. Why? Sexuality was not so narrowly defined.
This of course leads us to our world today where many people suffer from homophobia. Sex and the roles that men and women play are very narrowly defined, especially for men. For instance, it is ok for girls to wear blue but unacceptable for boys to wear pink. So, genetically most if not all people are born bi-sexual. However, due to the constraints our society puts on sexuality, most people will follow the path of least resistance and choose to go with the opposite sex, the socially accepted path. However, most people in their life time have experienced some attraction to the same sex, but once again due to the restraints in our society, they choose not to explore these homosexual urges.
So, is your sexuality an option? No, that's not what I'm saying but I'm saying most people are pressured into their sexual box by popular culture. For those that are gay, and I hate use that word because it really is an imaginary word, their inborn genetics simply don't allow them to follow so called societal norms, thus they follow their instinct and just go for the same sex. However, their are many gay people that are also somewhat attracted to the opposite sex as well, but for them gay is best and once again our society reinforces the idea that you are totally gay or totally straight. The evidence, and many studies have been done, show that most people are simply bi-sexual with many shades of grey. There is no clear cut answer or category that you can simply fit people into.
What about those homophobic people? It turns out that most of those people who turn to violence and hatred against homosexuals are themselves just simply repressing their own homosexuality. One recent study had two sets of people define their views on homosexuality. The study group was divided into two groups of men, those that thought homosexuality was a sin and totally wrong and those that were ambivilent towards homosexuality. The two groups of men were then showed both gay and straight pornographic material with sensors on their penis to record their arousal levels. You guessed it, those that were the most homophobic had the most arousal towards the homosexual pornographic material.
Thus, those that want to take away the rights of homosexuals are most likely just repressing their own true sexuality. They are afraid of being feminized, or as the ancients thought, being penetrated. So, George Bush is most likely very gay himself, nothing to be ashamed of but I just wish he would admit his bi-sexuality for we all are for the most part bi. Hey, why limit yourself to just one sex. The true question in sex is if you like to be the penetrator or if you like to the one penetrated. Personally, I like both.