Comment by Sam Solomon
In Â鶹´«Ã½ #117, there was a report of a meeting held in Melbourne around "Genetics and Sexuality".
The current controversy centres on an article by Dean H. Hamer and co-workers in the July 16 edition of Science. In it, the authors describe their isolation of a stretch of DNA on the tip of the long arm of the X chromosome (called Xq28) that was identical in 33 out of 40 pairs of homosexual brothers. These figures gave 99.5% certainty that the region is involved in sexual orientation. They have not tried to find a "gay gene", but rather some genetic basis to any sexuality.
This comes on top of recent work by several other researchers into finding a biological basis for sexuality. In 1991, the openly gay Simon LeVay published work in which he claimed to have found differences in the size of neuronal nucleuses between heterosexual and homosexual males. As well, in the past five years there have been several papers studying the sexuality of identical twins. Although not conclusive, these papers do suggest that there is evidence for heredity in sexual orientation.
At the turn of the century, researchers looking at the causes of human sexual orientation could find no common thread in the subjects they studied, and concluded that sexuality is "inborn". In the more recent past, many researchers tried to explain sexual orientation as a result of hormone levels. They failed. For a summary of the biologic theories of sexuality, William Byne in Archives of General Psychiatry (March 1993) provides a detailed analysis of all but Hamer's research.
The article in GLW quoted Ian Malkin as saying that a genetic cause of sexuality is unlikely. It is true that genetics will not be the sole determinant of sexuality, but the evidence does suggest that it plays a part. Malkin's argument that the next step would be to "cure" or eradicate the gene would seem unlikely, although detecting the presence of the gene could be used in pregnancies, the armed forces and other situations. Hamer has called for legislation preventing the use of his research for any discriminatory purpose.
Schuklenk's warning that many of the researchers are anti-gay is not true for any of the three main discoveries in the past five years. LeVay is gay, a reading of Hamer's article shows he is clearly not anti-gay, and Bailey has also made his position clear. However, some of the institutions sponsoring the research may be anti-gay. To counter this, society as a whole should have more control over the direction of scientific research, and the funding of the research should be made clear for all. The scientists should not be made scapegoats.
In capitalist society, gays and lesbians are oppressed, and the media have beat up every report of a biological basis to sexuality, in an attempt to isolate people from each other. However, to dismiss the idea that sexuality is partly determined by genetics is to ignore a huge amount of plausible and probably correct research.