There has been a lot of discussion over the cause of homosexuality. Many would prefer the biological explanation; if it is natural, then it is not wrong. These people delight in research that lent credibility to their arguments, primarily those dealing in the search for the "gay gene".
Well, just because something was researched "scientifically" it doesn't mean that it will be a truism. The scientific community is filled with debunked theories. JB Satinover elucidates why homosexuality is not easily explained away with genetics.
If someone actually could pinpoint a particular gene or gene clusters that "causes" homosexuality, will suppressing the gene make a gay individual straight? And if it does, is it ethical to do so or to force gay individuals to undergo said treatment?
Personally, I think it takes a whole lot of different factors that determines something as complex as a person's sexual orientation. For those who have no plans to stick to vanilla heterosexuality, the world is a jungle out there. Sometimes, things are not so black and white; there are many men who get married and still have male lovers on the side (same with women) who will not consider themselves as gay or bisexual. This is why reading the term MSM (men who have sex with men) used in infectious diseases and other medical journal makes me snerk.
(Mind you, I do believe that labelling or defining yourself by your sexuality / sexual orientation is doltish.)
I am, however, a fan of the environmental influence on a person's sexual orientation theory. While experimentation with the various flavours of sex can come from a person's sense of adventure, situation (e.g. living in boarding school) and curiosity, sexual and emotional attraction is a different kettle of fish altogether.
But no matter how much Holywood would like to romanticise homosexuality and making it sound normal and attractive (I have heard of idiots who claim or want to be gay because it is cool), it is still a thorny path to tread and fraught with challenges both emotional and social.