Soundings

Most scientists reject the one-gene-one-trait theory as naïve

Sep 2007    

Have scientists discovered the gay gene?

PERHAPS the most frequently cited study that maintains the connection between genetics and homosexuality is that conducted by molecular biologists at the National Institutes of Health under the direction of Dean Hamer in 1993.

By examining DNA samples from self-identified gay men and other gay male family members, Hamer and his team claimed to have discovered a DNA segment called a “marker” on the X chromosome. Men inherit this chromosome only from their mothers, not from their fathers. By defining this marker more closely, Hamer and his team of scientists hope to identify a “gene for gayness” on the X chromosome. In his report Hamer, who is a gay man, concludes that there is a strong genetic basis for homosexuality, although he admits that the environment also has a part to play.

Scientists have found Hamer’s methodology questionable and his conclusions unconvincing. In the first place, Hamer did not check if straight men also share the marker in question. His theory would be disproved if only a few straight men were found to have the marker. The second and perhaps more serious flaw has to do with his definition of who is gay. Hamer only studied what he considers to be “real” gay men, that is, men who have never veered from the preference for men in their sexual activities. But because he ignores the large population of men who have sexual relations with men but who do not identify as gay, his research is seriously compromised. It simply fails to account for the diversity of sexual behaviours.

According to an article by the Council for Responsible Genetics, Hamer’s study is “currently under investigation by the Federal Office of Research Integrity for possible scientific misconduct, because one of the study collaborators alleges that Hamer suppressed data that would have reduced the statistical significance of the reported results”. Unfortunately the outcome of the investigation is not available to me at this writing.

Another study, conducted in 1991 by neuropsychologist Simon Le Vay with the Salk Institute for Biological Studies in La Jolla, California also argues that homosexual orientation is genetic. By examining the brain structures of gay and straight men, Le Vay concluded that a specific structure in the brain of gay men is smaller (about the size of the brain structure in heterosexual women) than in straight men. Le Vay concludes that there is a certain connection between homosexuality and biology.

Le Vay’s study, however, is seriously compromised for two reasons. Firstly, his observations were made on cadavers, and his evidence about the sexual orientation and practices of the people in life were at best circumstantial. And secondly, all the “gay men” died of Aids, which is known to affect brain structures. Thus scientists have generally found Le Vay’s conclusions unconvincing.

Space does not allow me to discuss the studies by Michael Bailey and Richard Pillard at Northwestern University and the Boston University School of Medicine that argue for a biological basis of sexual orientation. But many scientists have also found these studies problematic and inconclusive. Furthermore, most scientists reject the one-gene-one-trait theory as naïve because of its reductionism and determinism. Such theories fail to take human freedom seriously due to its simplistic correlation between genes and human behaviour.

Human beings are such complex creatures (profoundly different from the other animals) who interact creatively and meaningfully with their environment. Even Dean Hamer admits that it is ludicrous to reduce human beings to their animal prototypes. “Pigs,” he writes, rather humorously, “don’t date, ducks don’t frequent stripper bars, and horses don’t get married … Animals don’t speak, write love songs, build churches, or do a lot of other things that we consider worthwhile.” Human sexual behaviour, in other words, cannot be simply reduced to genetic predisposition.

But what if one day the one-gene-one-trait theory is proven to be true? What if scientists can demonstrate that homosexual orientation has a genetic basis? What if the scientific community and society at large accept the view that homosexuality is “natural”? Must the Church abandon its traditional position concerning homosexual behaviour and revise its teaching?

Here we must clarify what modern culture means by “nature”. From the time of the European Enlightenment, the concept of nature has been increasingly secularised, plucked out of its original context of a theistic worldview and the Christian doctrine of creation. “Nature,” according to this view, is defined by science and no longer by a religious metaphysics. Nature, then, is that which can be subjected to empirical observation and the scrutiny of modern science. According to this view, it follows that if a certain behavioural trait is the result of the presence of a particular gene, that behaviour must be “natural”.

For the Christian faith, however, what is natural, and nature itself, cannot be gleaned from the scientific study of the world. It is disclosed only by revelation. What is natural is not based on the way things are but on God’s original intention for the creation. The empirical study of the world cannot yield knowledge of the created order as God had intended it to be because ours is a fallen world. The world as we see it is denatured due to the Fall. In addition, the scientific instruments, methods and concepts that we use are also affected by the Fall.

When Paul argues that homosexual behaviour is unnatural (Rom 1:26-27), his assertion is not based on a secular understanding of nature or a particular social convention. Rather it is based on the doctrine of creation. Paul is referring to human sexuality as God had intended it when He created human beings male and female. In the same way, the Christian’s conception of what is natural cannot be based on scientific research but on God’s revelation in Scripture.

Dr Roland Chia is Dean of Postgraduate Studies and lecturer in historical and systematic theology at Trinity Theological College. He worships at the Fairfield Preaching Point in Woodlands.

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