Gay gene discovery has good and bad implications

The finding that male homosexuality has a strong genetic component should be a boon for gay rights – but it could backfire

FOR gay rights activists, it's a dilemma. Does it help or hinder their cause if science shows that homosexuality is partly or largely biologically determined, rather than a lifestyle choice?

On the one hand, if sexual orientation is something people are born with, and cannot change even if they want to – akin to skin colour or handedness – this should overturn the notion that people choose to be gay and could equally well choose not to be. That knowledge would help rebut those who suggest that gayness is the result of a morally unacceptable decision, or a psychological disorder. It might also help people who struggle to understand or declare their own homosexuality.

On the other, some could try to redefine homosexuality as a biological abnormality. There is no way to change people's sexuality, but if key genes are found, it might be possible to detect homosexuality before birth, or to "cure" people by altering those genes. Even the threat of this could be used to persecute: consider the ugly histories of prenatal sex selection and of coerced and ineffectual "therapies" for homosexuals. It is no wonder that some activists see in such research the "seeds of genocide".

This debate has rumbled on for years. But as we report this week, there is growing evidence that male homosexuality has a strong genetic contribution (see "Largest study of gay brothers homes in on 'gay genes'"). Other biological components of homosexual behaviour have also been found: brain structures that differ with sexual orientation, for example, and robust theories for how genes survive in the population despite rarely being passed on by homosexual people.

To socially liberal and tolerant people, this new knowledge will be entirely unchallenging. It is in circles where homosexuality is still considered problematic – of which there are many – that it could have implications.

There is some evidence that people who see homosexuality as biologically determined are more tolerant than those who see it as a lifestyle choice. But it is not clear which way the arrow of causation points: it may be that tolerant people are more inclined to believe in biological determinism. And there is also a growing understanding that simply presenting people with evidence that contradicts their world views does not change their minds: rather than assimilate the information, they just intensify their efforts to reject it.

This seems a likely response among those who object to homosexuality. Homophobia has deep and complex causes. It may itself be partly biological in origin: for example, straight people with a stronger innate disgust response are also more likely to oppose gay marriage. You might as well ask: why not search for genes that make some people virulently homophobic?

Science cannot overturn such prejudice on its own, particularly when it clashes with world views that stipulate how society should be ordered. From these spring the urge to show that homosexuality is "unnatural", which the genetic evidence disputes. But human sexuality is in any case flexible and creative. Deeming certain behaviours unnatural is absurd: most of us have desires that could be labelled thus, and the natural world abounds with practices no human would attempt.

Ultimately, what causes homosexuality doesn't matter as much as the fact that homosexual people exist, and have always existed, in every society on earth. In the words of the activists: some people are gay. Get over it.

This article appeared in print under the headline "Get over it"http://www.newscientist.com/article/mg22429963.700-gay-gene-discovery-has-good-and-bad-implications.html#.VHS271eUdss