Talk to a bigot and they will tell you it's a choice, an ugly lifestyle, and spout a few verse from a man-made holy book. They can't let it be a innate thing, because then it takes away their control, and it's always about control with their crowd.
Now talk to science. Unfortunately for bigots, science tends lean towards the gay side. Not that bigots care what science have to say, mind you. The evidence is there, though. Increasingly, scientific studies are showing that homosexuality has a strong genetic factor.
Though, it's not understood how or why. Genetic studies are still making it's way in completing the picture of a lot of other human traits. We still, for example, have conflicts over why OCA2, one of the genes responsible for light skin pigmentation and albinism's, was selected. Though we have evidence that it was strongly selected in some population and developed as a result of genetic drift in other populations. The genetic components of homosexuality (in males, at least though it could very well be the case for females as well) is revealed be inheritable matralinially. In fact, it appears that male homosexuality may increase reproductive fitness in females and possibly inherited through the X chromosome. However, genes are not islands. Some traits are influenced by both genes and the environment. Some genes code for more than one trait or function. Some traits or functions are covered by more than one gene. All these will influence the study of the genetic component of Homosexuality. Drawing back from OCA2, it's expression changes from area to area. It's also not the only gene to code for light skin: SLC45A2 and MC1R also covers skin pigmentation as well as other necessary functions. Further study is needed to understand these things. But the evidence that it exist is there. And one thing is clear: it's being selected for.
Why is it being selected?
It's hard to say. One of the theory is that homosexual individuals will increase the reproductive fitness of siblings. A sibling's child is actually very closely related to the individual in terms of genetics. They're pretty much almost like you're own child. This theory is called the gay uncle/aunt theory. It could also be due to the fact that being gay doesn't actually affect reproductive fitness, because a human homosexual individual still can sexually reproduce. Another aspect is that it maybe a social community development. In the same way females ant and bee workers are not sexual reproductive but important aspect in keeping their species functional, homosexual individuals may have the same function. In many animals, homosexual individual can and do adopt children and provide care for other members of their species. Homosexuality may also be selected for because the genes involve may code for something else. APO-E is a gene that is necessary for catabolism but also have strong links to Alzheimer's. Alzheimer's is then selected for. Since Alzheimer's doesn't affect the fitness of the individual during their reproductive life, it isn't a hindrance.
What are the implications?
DNA Magazine's issue 121 published an article entitled "The Science of Sexuality" and posed a question that provoked me to write this pieces:
"What happens if a specific gene or biological trigger is identified as being
responsible for same-sex attraction? Could that mean there'll be a 'cure'? Will
some zealot try to eradicate homosexuality?"
The answer is yes, zealots will try. Zealots have tried. They have tried with stuff like eugenics. They've tried with race, with class, and recently against lesbians. But it won't work. As I've stated before, it's likely that these gene has more than one function . There fore any attempt and shutting them off will result in shutting off an necessary function. More over, we can't do it for ethical reasons. If we can shut off homosexuality, then we can shut off a whole lot of other traits. We'd be eliminating the natural diversity of the of the human genome. We should pride our self on being different. We shouldn't strive to make the human race look and act like clones. We're humans. Homosexuals are humans with a different variable on sexual attraction. As long as our relations remain consensual (somethings fundamentalist can't seem to fathom), we're harming no one.
Edit: I'm also a fan of being different. People can chose the life that they want to chose as long as they do not harm other people or infringe on other people's rights. That's right fundies, you can believe whatever the fuck you want as long as you don't infringe on other people's rights.
Iemmola, F., & Ciani, AC. (2009). New Evidence of Genetic Factors Influencing Sexual Orientation in Men: Female Fecundity Increase in the Maternal Line. Archives of Sexual Behaviors. 33(3), DOI: 10.1007/s10508-008-9381-6
Edwards, M., Bigham, A., Tan, JZ, Li, SL., Gozdzik, A., Ross, K., Jin, L., & Parra EJ. (2010) Association of the OCA2 Polymorphism His615Arg with Melanin Content in East Asian Populations: Further Evidence of Convergent Evolution of Skin Pigmentation. PLoS Genetics, 6(3), e1000867
Johanson, HC., Chen, W., Wicking, C., & Sturm, RA. (2010) Inheritance of a novel mutated allele of the OCA2 gene associated with high incidence of oculocutaneous albinism in a Polynesian community. International Journal of Cancer, 125(4), 909-917
Mengel, J., Wong, TH., Morling, N., Rees, JL., & Jackson, IJ. (2009). Genetic determinants of hair and eye colours in the Scottish and Danish populations. BMC Genetics, 2009, 10, doi:10.1186/1471-2156-10-88
Bailey, JM., Pillard, RC., Dawood, K., Miller, MB., Farrer, LA., Trivedi, S. & Murphy, RL. (1999) A family history study of male sexual orientation using three independent samples. Behavior Genetics. 29, 79–86