I think both have an influence in homosexuality, but since I had to pick one I am will pick genetics since there has been studies that cannot deny that there is some genetics has an influence in homosexuality.

I read this article about twin studies that was very interesting.

The main conclusions were:

1. No scientist believes genes by themselves infallibly make us behave in specified ways. Genes create a tendency, not a tyranny.

2. Identical twin studies show that neither genetic nor family factors are overwhelming.

3. We can foster or foil genetic or family influences.

4. Change is possible.

Here's the problem with genetic predisposition being the cause of homosexuality.

1. If they are genetically disposed to be gay, they are defective and must be cured.

Speaking to the issue of physical sexual desire, would anyone seriously contend that heterosexual desire stems from social learning? Absurd.

Given the stigma that is still associated with homosexuality, why would anyone "choose" to desire someone of the same sex? It'd be a hell of a lot easier to do what the majority is doing. You can't choose your desire.

But it's more than just physical desire that makes people fall in love. There is a mental/spiritual component, too. And I think that is also innate, and anyone who tries to label that as an environmental interaction is 'shrinking' what it means to be a human being.

There is an unfortunate tendency among heterosexuals to magnify the sexual dimension of homosexual relationships. Homosexuals seek companionship, security and fulfillment just like everyone else.

It most likely is primarily genetic. But, regardless of nature or nurture, it is NOT A CHOICE. You can't CHOOSE who you happen to be attracted to. I'm gay and I'm 5 foot 9, and I chose neither my height nor my sexual orientation.

I see there being a fundamental misconception in this "choosing" to be gay.

Our brains do, indeed, begin as a near blank slates, and most of our higher functions are learned post-birth (imagine what a Botswana-teenager believes to be a hot-babe versus a Hollywood-fed American teen). We define ourselves and our desires by veiweing others in our cultural context (while chemicals in our brain say "I am horny right now" we then define what to seek under these circumstances... be it a man or a woman... or a skinny or fat or blonde or brunette..black or white).

BUT, thinking that we CHOOSE to be gay, assumes we have an actual point in our childhood where we sit down for a good life-assessment and finally block-in A or B.

My argument is that while our biological disposition cannot yet be definitively proven to favor or not favor being gay- I think that we simply are not conscious of our attractions until a much-later age (perhaps self-awareness of cultural forces defining 'attractive'' occurs in our late-teens) and that any 'damage done' occurs without our fully self-conscious selves not yet being awake.

Our youth and development is on mainly auto-pilot and so a so-called choice is no choice at all- but more a cultural and sociological push- well out of our self-conscious hands until AFTER we are self aware.

Could you un-learn to be gay or straight then? Perhaps, but our youth-development is a hard force to dodge let alone divert completely.

Personal experience tells me that environmental factors cannot entirely influence someones sexual orientation, but can influence one's views on the subject, thus bringing any genetically caused feeling out into the open. I am an identical twin, I'm gay yet my twin is straight. We are both male, had the same stable upbringing and are very close. Obviously this must be to do with genetics, and the balance of sexual orientation in a person, not their environment.

I believe that I was born bi-sexual. I didn't choose it. Whether it's fully genetically determined, or environmentally determined, one's sexual orientation isn't a concious choice. I suspect that orientation is primarily genetic.

This is simply a matter of how the brain works. The brain learns everything it knows, even how to regulate breathing and the pumping of the heart. The only thing found in our genes is the design of how the brain learns and develops, but most of the development of the brain is done through learning. If we learn how to see, how to speak, how to love, and everything about ourselves from our mother, our family and society, then most definitely we learn how to love from them as well, and this includes straight and homosexual loving.

This argument, however, does not advocate that homosexuality is a "disease", because that implies that "normalcy" is in straightness. However, straightness is as randomly concieved and socially constructed as gayness. The reason why there are more straight people than gay people, then? Because straighteness is more socially rewarded. Why? Because it is better for society. Homosexuals cannot produce offspring, and this is our ultimate biological goal, and, yes, our most basic impulses are biological.

However, most of our behavior, though influenced by our most basic influences, are nuanced by social interaction. And so, what our brain learns about loving at an early age will determine later homosexuality or heterosexuality. Thus, both are determined by "environmental factors".

So, this also doesn't mean that anyone "chooses" to be gay or straight. The predisposition is made by our brain in an unconcious way. Still, the defining factors for homosexuality and heterosexuality (both) are learned (also unconciously).

Why? Because this is how the brain works.