Biology to sway the Vatican?

Research that attempts to find the cause of homosexuality is inherently a social and political enterprise as well as a scientific one. This is the proposition that informs Simon LeVay's review of such attempts. He follows others in relating how, right from the start, serious biological work on the origins of sexual orientation has been bound up with political activism. But he is also optimistic about the ultimate political implications of such research today, which he sees as reinforcing a historical trend toward increasing tolerance of gay behaviour and gay identity.

LeVay, a former Salk Institute neuro-anatomist and himself a gay activist, is the author of one of the two most frequently cited studies of possible differences between heterosexual and homosexual men. In 1991, he published a report in Science suggesting that a tiny piece of neural tissue - the third interstitial nucleus of the anterior hypothalamus, to be precise - was two or three times as large in the dissected brains of adult heterosexual males as in homosexual males. As with other such studies, which normally proceed from broader work on possible differences between the male and female brain in various species, LeVay's findings have been disputed on various grounds and not (as yet) replicated. But nor have they been discredited, and his remains one of the strongest claims for a biological correlate of human sexual orientation. It does not say which is cause, which effect, but it is at the least suggestive of a neurobiological signature for gay or straight identity, and of a possible research programme. LeVay thinks that such a research programme will go far, arguing that "when future research has delineated the entirety of the sexually dimorphic circuitry within the human brain and has established which parts of this circuitry are sexually atypical in homosexual individuals and which are not, it will be possible to form a more educated hypothesis about the brain basis of sexual orientation."

Here LeVay speaks with first-hand scientific authority. Elsewhere he turns reporter, for example when describing the second most frequently cited recent study. This, of course, was the 1993 report, again in Science, which was widely read as indicating the existence of a "gay gene". The work of Dean Hamer and colleagues at the United States National Institutes of Health, it indicated a linkage between genetic markers on the X chromosome and male sexual orientation. The exact location of the putative gene, or what it might do, remains unknown.

The two studies together have given rise to a great deal of comment, interpretation and speculation, as well as further research. Hamer's book on the gay gene, The Science of Desire, has already appeared. Both LeVay and Chandler Burr now try to put the research into a broader context.

LeVay looks at a range of themes in the search for an explanation of same-sex orientation, starting with the origins of scientific research on the matter in Germany in the 1890s, when Magnus Hirschfeld, developing the ideas of Karl Ulrichs, envisaged a "third sex". LeVay moves on to cover work on the prevalence of same-sex orientation, psychoanalytic accounts (typically involving defective parenting and only widely discredited in the 1970s), behaviourism, and hormonal studies, before coming to neurology, prenatal stress and genetics. He then discusses the emergence of the view that homosexuality is not a disease, marked by the American Psychiatric Association's deletion of the condition from its Diagnostic and Statistical Manual in 1973, and the legal position of gay men and women.

Throughout, the book leans towards the reductionist end of the scientific spectrum, and towards essentialism rather than social constructivism. For LeVay, constructivism leaves him nothing to study, seeing human identity as a kind of shell, marking the interface between an individual and his/her environment. He believes, rather, that "in truth we have a core identity, of which our sexual orientation is an important element, that radiates outward and richly informs and energises our lives, helping to make each life unique."

Chandler Burr offers much the same view in A Separate Creation, which focuses on the more recent research. Burr is a political journalist who has taught himself enough science to discuss current work with many biologists, and especially geneticists. He has produced a much more useful book than suggested by his publisher's publicity, which offers nonsense about curing homosexuality with antibiotics, and silicon chips made of DNA. Although more selective than LeVay with some of the evidence about distribution of sexual orientation, and still wedded to a few scientific misapprehensions, Burr has asked all the right questions of the right people and thought seriously about the answers. He is especially good on what it might mean were a trait such as homosexuality to be genetic. But the main virtue of his book is that, while LeVay mainly reports results, Burr acquaints the reader with the researchers behind the data, and with the way they debate their disagreements and differing interpretations of their findings.

This gives a vivid impression of how science proceeds, as well as showing the range of positions that may arise from LeVay's contention that the research is inevitably loaded with social and political implications. The Harvard population geneticist Richard Lewontin, for example, has long been an opponent of such studies. His present position, as reported by Burr, appears to be that Hamer's genetics constitute perfectly good science - but Lewontin still wants to know, why do we need to ask what role biology plays in sexual orientation? The very act of asking a scientific question gives that question a special significance.

The wider view of human sexuality offered by Paul Abramson and Steven Pinkerton helps to put Lewontin's objection into perspective. These two University of California at Los Angeles psychologists review a large variety of studies of sex and sexual behaviour, in a book loosely organised around the simple theme that the pursuit of pleasure is not subordinate to the urge to reproduce in driving human sexuality, but of equal importance.

This view is woven into an account of sexual practices that ranges widely across disciplines, times and cultures. The book is sometimes poorly organised, but it does make the concerns of the contemporary science of homosexuality appear a little parochial. For Abramson and Pinkerton, homosexual behaviour is neither as simple nor as stable as LeVay and, to some extent Burr, want to suggest. And they want to incorporate the debate about the origins of homosexuality into a larger inquiry: "The question that interests us is not whether biology or the environment is the greater contributor to sexual orientation, but how these influences interact in different people to produce the variability in sexual object 'choice' evident throughout history, both within and across cultures."

But this inquiry, as the book makes clear, is too general to receive answers in our present state of knowledge. As Abramson and Pinkerton's account proceeds, it turns into a series of discussions in favour of a conclusion that appears to be: "If it feels good, do it (but preferably with a condom)". This is intellectually unsatisfying, whatever its other rewards.

The inquiry Lewontin objects to, by contrast, looks as if it is making some scientific headway. But this still leaves open the question: why should it matter where sexual orientation comes from? In LeVay's words, who cares?

His answer is that, for science, one might argue that the question is not important, but for our society it is. LeVay is convinced that if everyone believed homosexuality had biological origins, the case for gay rights would be immeasurably strengthened. Burr goes along with him part of the way, although he has more reservations about the potential applications of such biology.

In particular, LeVay thinks such a discovery would end efforts to alter gay behaviour by "treating" homosexual orientation. He offers a wealth of historical examples of attempts to "cure" male homosexuals. These were coercive in effect, if not invariably in intent - if, that is, they had any effect at all. The only unambiguously documented outcomes, he argues convincingly, were men who claimed they no longer experienced same-sex attraction in order to get the treatment to stop. More common were cases like that of "one unfortunate man, an inmate of Worcester State Hospital, Massachusetts, who was treated sequentially with three different oestrogen preparations, as well as with testosterone, gonadotrophins, thyroid powder, and pituitary extract, over six months in 1939 and 1940. His homosexuality remained unaffected, as did his other traits." This is plainly a tradition well worth bringing to a final end, but would a biological account of gay identity help to achieve this? LeVay's argument that it would, rests on at least two assumptions. If homosexual behaviour is shown to be strongly biologically determined, society will see it as "natural"; furthermore, it will be seen as acceptable. He may be right that the immediate political effects of locating a gay gene would follow this line, but neither social attitude is a logical consequence of a belief in biological determination.

Whether or not some condition is under strong genetic influence need have no bearing on whether it is generally regarded as normal or pathological. Where behaviour is concerned, it may bear on questions of responsibility or blame, but these have no necessary connection with acceptability. If I had a neurological condition with a postulated genetic aetiology that led me to make love to my daughters, I would still expect to end up in court, whatever expert arguments might then ensue.

On the question of changing sexual orientation, the research is inevitably double-edged. Yes, it may be true that some people who are antigay would change their beliefs if they became convinced that homosexuality was not a matter of personal choice, though the position of, say, the Catholic church suggests such expectations are only partly justified. As LeVay points out, the Vatican line is that permanent homosexuals may be less deserving of censure for their feelings, but must still curb their behaviour. "Sexual relations between persons of the same sex are necessarily and essentially disordered according to the objective moral order," says the Vatican Council.

In the face of such absolutism, there may well be gay men who would want to avail themselves of genetic technologies of shifting their sexual orientation. This is the double edge. The genetic, if not the neuroanatomical, research line may simultaneously offer a persuasive account of the biological origins of homosexuality and a means of "curing" it, if, after all, sexual orientation is no different from any other trait. The assumption behind the human genome project is that if we understand the genetic structures underlying particular phenotypes, we may be able to alter them.

As things stand, the likelihood is that any gene involved in same-sex orientation is going to influence early neurodevelopmental events, so the prospect for engineered change in adults is very small. But there are reputable scientists who believe it is possible.

In the end, both Burr and LeVay take a permissive attitude towards the uses of any future genetic technology. They suggest there should be no bar to testing for any robust indicator of sexual orientation; that here, as elsewhere, we must be open to individual choices. And LeVay argues that if there were a technology that (unlike all those tried in the past) could alter sexual orientation, there would be good reasons to try to dissuade a gay man from using it, but not to prevent him.

This solution to all the problems of social decision-making by making individual choice paramount is in line with LeVay's general optimism. For others, the cup may appear as half empty rather than half full. As a key piece of evidence for the positive effects of an essentialist view on tolerance toward gays, LeVay cites a US poll in 1992 that found that 71 per cent of those who believed that homosexuality is a choice would object to a homosexual being employed as a primary school teacher. Among those who believed that being homosexual was not something a person could change, the percentage of objectors fell to "only" 39 per cent. That still leaves an awful lot of people to be persuaded.

Jon Turney is lecturer in science and technology studies, University College London.