In my view there are two possibilities for the determination of sexuality, genetic, and social. It is either determined by some genetic principle(hence people are born gay), or it is determined through complex social interactions. Or possibly the ever popular, "people choose to be gay".

Personally I think sexuality is largely determined by social factors. I'm sure certain genes influence personality in such a way that it makes the social factors act in order to bring about a person's sexuality, but generally it is these social factors that take the need for sex, and form it into a desire for sex with certain groups of people.

To illustrate my point all you have to do is look at the Hellenistic World, ancient greek and roman men were often bisexual, and this was socially acceptable, even encouraged. Usually older men engaged in relationships with young men in the later teens. Today such relationships are seen as abhorrent and wrong, and only very rarely do they exist in our society. Now as homosexuality and bisexuality become more acceptable in our society, it seems as if more of these people are cropping up, especially among adolescents(suggesting social factors during puberty are dominant in determining sexuality). Historical differences in sexuality can't be looked at as Christian society suppressing natural tendencies, because social factors in societies with widespread bisexuality or homosexuality often encouraged such behavior.

Of course you can't say people choose their sexuality, anymore than they can choose their body language, or native tounges. It may be possible, if you really tried, to change your sexuality, but I highly doubt that throughout history alternative sexuality has been determined exclusively through acts of will.

What do you think?