Leading Article: Gay genes do not exclude choice

PIECE by piece, the evidence is mounting that genetic factors help to predispose people towards homosexuality. Since 1990, three sets of research have established that different parts of the brains of homosexual men are either smaller or larger than in heterosexuals. Now, as we report today, scientists at the National Cancer Institute, in the United States, have located a region of the X chromosome - which men inherit solely from their mothers - that they believe plays a crucial part. The researchers believe they are thus nearer to pinpointing the precise genes that may produce the predisposition.

Until these findings began to surface, it was generally assumed that homosexuality was a matter of free choice conditioned by upbringing. Parents may have been held to play a large role in the shaping of their children's sexual orientation; Freud and his followers having pointed accusing fingers at over-loving mothers and inadequate fathers. But parents were not thought responsible for actually passing on a tendency to homosexuality, like one to left-handedness. It is unfortunate that once again mothers seem likely to take the main blame.

It seems unlikely, however, that any scientist will ever be able to establish just how strongly the relevant gene predetermines its bearer's sexuality. While an element of choice remains, the latest findings will probably not bring about a dramatic change in attitudes, let alone in the law. In the United States, for example, there have been predictions that anti-discrimination legislation which protects people with immutable characteristics, such as race, would have to be extended to gays should homosexuality also prove to be an immutable characteristic. It seems improbable that being gay will ever be seen as no less inevitable than being black. Even if it were so, the experience of blacks does not suggest it would spare them discrimination.

The greater danger is that a hereditary predisposition to homosexuality might be considered in the same light as a hereditary disease: at best curable, at worst, grounds for an abortion. Leaving aside the Hitlerian eugenic attitudes implied, only a glance is required at the list of homosexual geniuses down the ages - from Michelangelo to Britten, Bacon and Nureyev - to show the catastrophic loss that would inflict on mankind, and not just by eliminating geniuses. The contribution of homosexuals to making society more civilised and less brutal can hardly be overestimated.

The happiest outcome of the latest research would be to reduce the intolerance that homosexuals encounter in virtually all fields except show business and the rag trade. Religious fundamentalists would find it harder to label homosexual behaviour a sin. Parents could cast aside fears of their children being corrupted by gay teachers. More importantly, homophobes might come to appreciate that sexuality is an infinitely complicated matter, in which nature and nurture play roles that are likely to remain hard to unravel.