I've stayed out of this, but I will say one thing. I definitely don't believe that it's a "Nurture" thing. I don't believe it's how your parents raised you. I do believe however that the "Sexual Preference" part of humans is a socially learned/adapted quality. Just like some people are attracted to blonds vs brunettes; Caucasians vs African; large women/men vs petite; tall vs short; etc... Now obviously, there are internal triggers that are in concert with this social exposure that presents a preference on way or another. This is a part of physiology and biology/chemistry that no one knows the answer to. But the desire to have "Sex" in biological, while the "Preference of WHO to have sex with" is more socialized and simply a preference. A person's DNA doesn't decide that they prefer Heavy women compared to tiny women.
Now; that is purely the "Sexual" position. Homosexual/Heterosexual is a lot deeper than Sex. It's also about relationships, love, trust, companionship, etc... Some men's BEST FRIENDS are other men. Some are WOMEN. Some women's best friends are other women; some are MEN. Some prefer to be around the same sex all the time; some prefer to be around the opposite sex all the time. A lot of this is socialized. The relationships you had when you were young. Who could you trust? Who didn't you trust? Who comforted you and who caused you stress? You can see this with children. "Momma's Boy", "Daddy's little girl". Sometimes the boy is closer to his father and men in the family. Same with girls and the women in her family. This is a combination of socialization and the internal triggers that provide pleasure and preference vs dislike and/or stress. Again; a part of the physiology, biology/chemistry of the human being that can only be theorized and isn't known for sure.
While it's true that other animals/mammals have exhibited homosexual tendencies, with the exception of a very small number test subjects like a couple of sheep I believe, most all other homosexual actions by non-human animals were short term. Either as a form of power and dominance, or simple physiological need. Almost all occurrences eventually went back a permanently mated long term with the opposite sex. Now this doesn't prove conclusively that sexual preference is totally a socially learned trait. But it does prove that the social environment does in fact play a part in it. Physiologically/biologically; humans are more complex than lower level animals. Our ability to "PREFER" certain attributes is more complex. So while I believe that there are physio/bio/chem factors that factor into a person's "Preferences", I believe that these must be accompanied by social experiences and exposure to determine the final product.
"Disclaimer": This position/opinion was based on clinical and abnormal psychology and sociology as a behavioral science major in college. (30 years ago). And NO, the "Abnormal Psychology" portion didn't presume that homosexuality in itself was "Abnormal". It treated "Abnormal" as any 2 opposing positions. Fat vs thin, gay vs straight, black vs white, country boy vs city boy, etc... Basically, anything different than what the individual considered NORMAL to THEM. The sociology side of this emphasized behavioral changes based on society and the influence of others on the individual's decisions and preferences.
