We are born as a blank slate, neither heterosexual or homosexual. All animals, in my opinion, are bisexual by nature since sex is a primal instinct. That’s why dogs hump each other, etc. We’re raised to believe heterosexuality is the only “correct” sexuality, but homosexuality has been around forever. Only because of the dominance of religious dogmas (ie. Catholicism) do we shun homosexuality in modern societies. In reality, everything is a choice. We can choose whether to only fornicate with the opposite sex, or the same sex, or both. It may be just for fun (sex for pleasure – again, a primal instinct) or to satisfy sexual urges. In prison, the oppression of sex from the opposite gender causes many inmates to act out homosexual tendencies to relieve their natural instinct.
During puberty, when hormone levels are raging, many are often curious, because as aforementioned, we’re born a blank slate; therefore, experimentation is only natural, and will lead you to realize that sex is sex regardless of whom it is with. Once we settle on our identity we may find one gender more appealing and may choose to solely be satisfied by that gender and identify as homosexual (or gay/lesbian). Ultimately though, I believe even the “straightest” people have, at one point or another, had some kind of homosexual thought, and even that doesn’t make you “gay” unless that is what you choose to be identified as. Furthermore, I believe people should be respectful and tolerable of others’ sexual expression. There is no “right” or “wrong” in terms of your sexuality.
I would also like to add that gay marriage shouldn’t even be a debate. It is again due to prevalent religious dogmas (namely Catholicism/Christianity and the like) that claim “marriage” only applies to their religion, and is defined as “a man and a woman” which is arrogant to say the least. Marriage is the binding commitment between a couple in light of compassionate love. A couple does not solely mean a man and a woman, and everyone has the right to be with whomever they please. Religion shouldn’t and doesn’t own the right to “marriage”.