I have not really joined in the discussion here about whether homosexual behaviour is a result of nature or nurture although I think, in many ways, it is absolutely pertinent to the original subject of the thread..

If it was possible to prove people were born gay it would probably give them wider social acceptance as an American Conservative think tank expressed it
"(it) would advance the idea that sexual orientation is an innate characteristic, like race; that homosexuals, like African-Americans, should be legally protected against 'discrimination;' and that disapproval of homosexuality should be as socially stigmatized as racism"

In the last decade polls have shown that this "biological" argument has gained momentum especially amongst young Americans.

Some advocates of gay marriage argue that proving sexual orientation is inborn would make it easier to frame the debate as simply a matter of civil rights, which view point we have seen represented quite forcibly in this thread.

An alternative belief that has also been equally strongly expressed is the one that dominated the thinking during much of the 20th century that is to say that homosexuality is connected to upbringing.

Freud, for instance, speculated that overprotective mothers and distant fathers helped to produce homosexuality

Since then there hasn't been much science produced to support the old, generally rejected, theories tying homosexuality to upbringing and it has been argued that Freud may have been seeing the effect rather than the cause, since a father faced with a very feminine son might well become more distant or hostile, leading the boy's mother to become more protective.

Cornell psychologist Daryl Bem has proposed an intriguing theory for how childhood gender nonconformity CGN might lead to homosexuality which stresses environment over biology but still considers this pathway to be triggered by biological traits

The American Psychiatric Association finally removed "homosexuality" from its manual of mental disorders until 1973

In 1991, Simon LeVay, a neuroscientist in San Diego claimed he had found a key difference between the brains of homosexual and heterosexual men he studied
A small clump of neurons of the anterior hypothalamus - which is believed to control sexual behavior - was, on average, more than twice the size in heterosexual men as in homosexual men.
Although, theoretically, the clumps could, have changed size because of homosexual behaviour that seemed unlikely, and the study ended up jump-starting the effort to prove a biological basis for homosexuality.
Studies of identical and fraternal male twins demonstrated that there was a greater chance of both being homosexual than the usual incidence in the population and homosexual brothers were found to share a specific region of the X chromosome, called Xq28, at a higher rate than gay men shared with their straight brothers.

However the studies for biological origins have been small and underfunded, and the results have often been modest.

The gay gene theory has taken some hits; a Canadian team was unable to replicate the findings and a team from Dean Hamer's own lab reported only mixed results after having done the first scan of the entire human genome in the search for genes influencing sexual orientation.

LeVay himself is quoted as saying
."But it's also kind of frustrating that it's still a bunch of hints, that nothing is really as crystal clear as you would like."

In 2005 Swedish researchers reported finding important differences in how the brains of straight men and gay men responded to two compounds suspected of being pheromones

This research once again connecting the hypothalamus to sexual orientation comes on the heels of work with sheep. About 8 percent of domestic rams are exclusively interested in sex with other rams; researchers had found that a clump of neurons similar to the one LeVay identified in human brains was also smaller in gay rams than straight ones; although again, admitted that it was conceivable that these differences could be showing effect rather than cause.

During fetal development, sexual identity is set before the sexual organs are formed perhaps it's the same for sexual orientation


By now, there is substantial evidence showing correlation - though NOT causation - between sexual orientation and traits that are set when a baby is in the womb
The research suggests that early on in the womb, as the fetus's brain develops in either the male or female direction, something fundamental to sexual orientation is happening.
But -nobody's sure exactly what's causing it.

To conclude, all the research, at present, suggests that, while post-birth development may well play a supporting role, the roots of homosexuality, at least in men, appear to be in place by the time a child is born

But there is simply no consensus about the exact reasons that an individual develops a heterosexual, bisexual, gay, or lesbian orientation. and, while the doctrines of the world's largest religions generally view homosexuality negatively, concerns will continue to be expressed about such unions on religious grounds
However, in the light of increasing research the Rev. Rob Schenck, a prominent Washington, D.C., evangelical leader, said that he no longer believed homosexuality to be a life choice and, while still an opponent of homosexual relationships, warned that
"If it's inevitable that this scientific evidence is coming, we have to be prepared with a loving response. If we don't have one, we won't have any credibility."


The legalization of same sex marriages (as opposed to civil unions) may also be argued by some to be an attempt to impose the concept of homosexuality as an immutable characteristic analogous to racial determinants in the absence of any empirical evidence.
But, if the theory of maternal stress during pregnancy resulting in the release of androstendione is correct then the process is environmental and potentially preventable.


Others may perceive societal impacts and indirect consequences of same-sex marriage (for example a redefinition of marriage opening the door to the right to have polygamous marriage)
I hear that there is a strong lobby for this oppressively paternalistic and ultimately (given the proportions of men to women in the population) socially inequitable form of heterosexual 'marriage' in some American states



I'll look in again after the next 1688 posts