How the "Gay Gene" Model Caught On. (Books).
by Robert Alan Brookey
Indiana University Press
167 pages, $27.95
THE HOOPLA around the "gay gene" has died down somewhat since the early 1990's when both the gay and the popular media gave it front-page coverage. Michael J. Bailey's and Richard Pillard's familial studies of sexual orientation in twins revived a research angle suggested in the 1950's by eugenicist Franz J. Kallmann Bailey and Pillard found that the concordance rate for homosexuality (i.e., both siblings have the same sexual orientation) was higher in monozygotic (identical) twins than dizygotic (fratemal) twins. Furthermore, the concordance rate was higher in dizygotic twins than non-twin siblings. This suggested that there was a strong hereditary contribution to homosexual orientation. Bailey and Pillard acknowledged that since the concordance rate in their research sample was not 100 percent (as had been the case in Kallmann's problematic study), other factors, such as upbringing and experience, played a role.
Hamer's scientific articles made it clear that he had not found a "gay gene" but instead an association between genetic markers on Xq28 (a segment of the X chromosome with several hundred genes) and the trait of homosexuality in forty pairs of gay brothers. In other words, the gay brothers were concordant for particular markers (DNA sequences) on Xq28 significantly more often than expected by chance alone. Furthermore, he had specifically selected pairs of gay brothers with family trees that did not have gay relatives in the paternal line. This allowed him to focus his search on the X chromosome, and it increased the odds of his finding an association with the X chromosome if it is maternally transmitted in males. (In most human males, the mother contributes the X chromosome and the father the Y)
Dean Hamer and his colleagues took the next step of searching specifically for genetic factors i nfluencing sexual orientation. In a 1993 article and in a popular book the following year, Hamer tried to demonstrate a linkage between genetic markers on the X chromosome and male homosexuality. A subsequent paper (in 1995) replicated these findings but failed to find any linkage between the X chromosome and sexual orientation in women.
Despite the limited and statistical nature of Hamer's results, the popular press simplistically presented the findings as proof of a "gay gene." Many academics in science studies (including this writer) have pointed out the conceptual, methodological, and political problems of this current wave of biological research on homosexuality. One of the great dangers of work such as Hamer's is that preliminary positive findings get tremendous media attention, while the numerous negative or contradictory studies get no press. The public is thus left with the impression that the gene for homosexuality, depression, or gambling has been discovered, when in fact there is no scientific consensus on any of these. In the case of the "gay gene," a study by George Rice and colleagues (1999) failed to replicate Hamer's findings in a group of 52 gay male sibling pairs from Canadian families. Yet this was not widely reported.
I was hoping Robert Brookey's short and readable critique of this work would correct this state of affairs. Brookey approaches the literature from a rhetorical perspective, examining the homophobic prejudices that have tainted research on homosexuality since the 19th century, not just in genetic research, but also neurobiology, endocrinology, and sociobiology. In particular, he points to the persistence of the "sexual inversion" model according to which gay men were thought to have a female soul or brain in a male body. The notion of inversion was even promoted by Victorian homosexual activists such as Karl Heinrich Ulrichs. This model permeates the researchers' obsession with effeminate men and masculine lesbians, who were poked and probed to reveal the sexually inverted nature of their bodies, hormones, and brains. For example, neurobiologist Simon LeVay's widely publicized study of the hypothalamus relied on the inversion hypothesis in trying to demonstrate that an area of gay men's brains--like that of wo men's--is smaller than that of heterosexual men.
Brookey's political argument is quite sensible. As Timothy Murphy and Ed Stein have also explored in greater detail, basing gay rights on the biological argument is very problematic. For over a century, homosexuality was treated in the medical arena as pathological. So it is ideologically worrisome to raise the biological evidence in courts in order to draw an analogy between homosexuality and disability so as to invoke the kind of legal protection provided by the Americans with Disabilities Act. Have other fixed biological traits, such as race or sex, been exempted from discrimination by the fact of their immutability? Civil rights should not be based on a group's biological traits but on general principles of equity.
Despite the wisdom of his theoretical stance, Brookey's hostility toward science or simply his poor grasp of biological theories and methodologies undermines his argument. He is especially ill-informed about genetics, particularly molecular genetics. He states that geneticist Richard Dawkins (known for his "selfish gene" hypothesis) argues that genes are digital. Not only does he misattribute this statement (which comes from Wired journalist Michael Schrage), but Brookey really means to criticize binary genetic models, not digital ones. (Digital systems represent data in terms of discrete digits, as opposed to analog systems which represent data by continuous measurable physical qualities.) He goes on to criticize Hamer for his "digital model" of sexuality, when really he means Hamer's binary model (subjects were rated as either homosexual or heterosexual). Finally, he claims Hamer posits that men either have the gay gene or not, grossly simplifying what Hamer or any geneticist would understand as a complex a nd uncertain relationship between genotype (the genetic code of a trait) and phenotype (the physical manifestation of a trait in an individual organism).
Elsewhere, Brookey states that, "By focusing on the X chromosome, Hamer theorized the gay gene as a female gene." While a catchy statement, it makes no sense scientifically. Both males and females have an X chromosome. Even Y, the "male chromosome," which for almost a century was considered the determinant of male sex in humans, has fallen in statute in the past decade. Molecular geneticists have discovered that male sex determination is extremely complex and relies on critical genes not just on the Y, but also on the autosomes (non-XY) and even the X chromosome.
Current research on sex and sexuality, particularly in molecular genetics, is fascinating and complex. It is advancing at a tremendous rate. Thanks to nanotechnology, we will soon be able to determine an individual's genotype through routine and inexpensive testing. How society handles this information is of vital importance to everyone, not just GLBT people. Critics and skeptics of this new technology are essential, but they must genuinely understand the science they are dissecting and not resort to superficial glosses and pop media scare tactics.
Bailey, J. Michael, and Richard C. Pillard. "A genetic study of male sexual orientation." Archives of General Psychiatry 48, 1991.
Kallmann, Franz J. "Twin sibship study of overt male homosexuality." American J. Human Genetics 4, 1952.
Hamer, Dean, Ct al. "A linkage between DNA markers on the X chromosome and male sexual orientation." Science 261. 1993.
Hamer, Dean, and Peter Copeland. The Science of Desire: The search for the gay gene and the biology of behavior. Simon & Schuster, 1994.
LeVay Simon. "A difference in hypothalamic structure between heterosexual and homosexual men." Science 253, 1991.
Murphy, Timothy F. Gay Science: The Ethics of Sexual Orientation Research. Columbia University Press, 1997.
Rice, G., et al. "Male Homosexuality: absence of linkage to microsatellite markers at Xq28." Science 284, 1999.
Stein, Edward. The Mismeasure of Desire: The Science, Theory, and Ethics of Sexual Orientation. Oxford University Press, 1990.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||Reinventing the Male Homosexual: The Rhetoric and Power of the Gay Gene|
|Publication:||The Gay & Lesbian Review Worldwide|
|Article Type:||Book Review|
|Date:||Jul 1, 2003|
|Previous Article:||Public Outings. (Books).|
|Next Article:||A Farewell to the Male Body. (Books).|