By Dave Riley
There are many human conditions that are clearly pathological which seem to have a genetic cause. Disorders such as Huntington's chorea and cystic fibrosis occur in people who carry the relevant mutant gene regardless of diet, occupation, social class, or education.
While such conditions are rare — 1 in 10,000 for Huntington's disease — other disorders, like sickle cell anaemia among people of West African descent, occur at a higher frequency but are less severe and more sensitive to environmental conditions.
The medical model that rests on such discoveries has so far failed to prove that diabetes or heart disease is similarly caused. However, it is generally accepted that some cancers have a genetic predisposition. Such genes, known as oncogenes, are thought to disrupt normal cell division, and the recently discovered mutant gene on chromosome 17 has been linked to the early onset of breast cancer.
Less founded in fact are the many claims over the last 20 years which insist that schizophrenia and manic depressive psychosis have a direct genetic origin. Regardless of the biochemical and genetic research lavished on these conditions — more so than any other in psychiatry — proof of an organic cause has not been found.
So a claim that a gene exists which causes homosexuality should be treated with considerable scepticism.
The medicalisation of homosexuality, by employing a gay gene to explain it, assumes that it is a pathological condition. In such a medicalised social world, human sexual behaviour is clearly divided between heterosexual and homosexual activity.
This description does not correspond with our knowledge of human sexuality. There is a continuum of sexuality that runs from the exclusively heterosexual through those who have a wider range of experiences, through those who are regularly bisexual, to those who are exclusively homosexual. A succession of polls in the United States has suggested that up to one half of the male population has had at least one homosexual experience.
Single sex male enclaves such as prisons tend to be more actively homosexual than similar populations outside. Unless this gay gene is a switch on, switch off again gene, or one that also has a proclivity toward crime, maybe we should review its ready predictability.
Aside from the problem of dealing with the corresponding suggestion that there is a gene for lesbianism, biological research in this area is greatly hampered by the fact that those who engage exclusively in homosexual behaviour leave no offspring. Very few of us can confidently say that grandad was gay. Since grandma did not then have access to artificial insemination, maybe we don't carry our forebears' sexual preference after all.
Another difficulty faced by the geneticists is that instead of homosexuality being linked to a specific thread of DNA, maybe it is bisexuality that is more readily transmitted at conception. "Indeed", writes geneticist Richard Lewontin, "we could make an argument that bisexuality is a manifestation of greater general libido, and it might turn out that bisexual people leave more offspring".
But the best argument against the gay gene is the rationale that biological determinism has employed to explain how it evolved. In some long ago time, so the story goes, homosexuals did not mate but helped their heterosexual brothers and sisters to raise more children. Such dedication to the prehistoric nest ensured that their relatives had twice as many offspring as usual so that the gene for homosexuality was kept in the population.
Anthropologically, such a scenario is extremely suspect, and the determinists have yet to find a more credible functional role for homosexuality that would explain its continuing presence on the human genetic tree.
While some people have welcomed claims of a gay gene because it supposedly proves biologically that homosexuals are born gay and therefore should not be oppressed for this reason alone, others have embraced the claim because it shore ups separatism in the gay community.
The willing acceptance of this attempt to isolate sexual preference and tie it to a specific biological cause is unfortunate. A readiness to go along with such claims placates an ideological offensive geared to convincing us, regardless of our sexual preference, that most of our social and psychological make-up is inherited. If gays are gay because of their genes, then maybe characteristics of gender, race and class are similarly "inevitable" rather than socially conditioned.