SCIENCE

‘Opening a window’

Genes may play a role in homosexuality

MARK NICHOLS July 26 1993
SCIENCE

‘Opening a window’

Genes may play a role in homosexuality

MARK NICHOLS July 26 1993

‘Opening a window’

SCIENCE

Genes may play a role in homosexuality

MARK NICHOLS

Ever since St. Paul lashed out against those whom he regarded as sexual deviates, the belief has persisted among some groups that homosexuals deliberately choose an “unnatural” way of life—and should be punished for their choice. Now, a growing body of scientific evidence is lending support to the view that homosexuality may be at least partly a matter of inheritance. In an article published in Washington last week in the journal Science, a research team led by Dean Hamer, a molecular biologist at the National Cancer Institute in Bethesda, Md., reported on a study of 40 pairs of gay brothers. The study found that in 33 of the pairs the brothers had the same distinctive markers near one end of the X chromosome. Hamer said that his team now planned to search for the gene involved. But he cautioned that such a gene was unlikely to be the sole cause of homosexuality.

And likewise the men, leaving the natural use of the woman, burned in their lust one toward another; men with men working that which is unseemly and receiving in themselves that recompence of their error which was meet.

—Romans 1:27

The importance of the study, said Hamer, is that it “opens a window inI to understanding how genes, the $ brain and the environment interact § to mould human behavior.”

Despite his disclaimer, the finding by Hamer’s team appeared to add significant support to a series of studies in recent years that have suggested that inheritance may play a larger role in determining sexual preference than was suspected in the past. Some gays and lesbians welcomed the latest finding as a step towards reducing hostility aimed at homosexuals. ‘This could have a beneficial effect,” said Simon LeVay, a gay Los Angeles educator and neurobiologist, who two years ago discovered distinctive features in the brains of homosexual men, “by undermining the type of homophobia that regards homosexuality as a perverse lifestyle.” But others warned that Hamer’s study could have more sinister implications. They pointed to the possibility of prenatal testing to determine the likely sexual orientation of an unborn child—and abortions by parents who

did not want to have homosexual offspring.

The finding by Hamer’s team was the third major study in two years to suggest that the origins of homosexuality may be partly genetic. In August, 1991, LeVay reported results from studying the brains of 41 male cadavers, including 19 homosexuals. He found that in the gay men a segment of the hypothalamus, which is in the base of the brain and is believed to be related to sexual drive, was significantly smaller than in heterosexu-

al men. Five months later, psychologist Michael Bailey of Chicago’s Northwestern University and psychiatrist Richard Pillard of the Boston University School of Medicine reported that in studying gay men with twin brothers, they found that 52 per cent of the identical twins studied were both gay, while only 22 per cent of fraternal twins, who have weaker genetic links with each other, were both homosexual.

In the latest study, Hamer said that his team decided to study the X chromosome, which men inherit from their mothers, after a preliminary study of 76 gay men showed that many of the men had homosexual relatives on their mother’s side of the family.

After testing with genetic analysis techniques, Hamer and his team discovered a group of five markers—recognizable locations in the genetic material—near the tip of the X chromosome. The report in Science speculated that the gene might play a role in the development of parts of the brain that influence sexual activity.

Among gays and lesbians, reaction to the finding was mixed. In Halifax, J. C. Aucoin, president of the Gay and Lesbian Association of Nova Scotia, questioned the need for research into the cause of homosexuality. ‘The whole approach implies that there is something wrong with homosexuality that needs to be fixed,” said Aucoin. “Regardless of cause, the fact is that some people are homosexual and deserve to be treated no worse than anyone else.”

LeVay, who currently is serving as director of West Hollywood’s Institute of Gay and Lesbian Education in Los Angeles, also expressed concern that evidence of a genetic basis for homosexuality could lead someday

to the testing of fetuses and to abortions by women who did not want to give birth to homosexual children. “That would be very sad,” said LeVay. “But I don’t think that the way to go is by not doing this kind of research. The only way to deal with such dangers is to work towards a society in which gays and lesbians are valued.” Given the virulent hatred that some people still direct towards homosexuals in society, and the debate that scientific findings about sexual preference inevitably provoke, it may take some time for the beliefs expressed by St. Paul nearly 2,000 years ago to be laid to rest.