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Mamma Mia, I Got Those Sexually Antagonistic Genetic Blues

Mamma Mia, I Got Those Sexually Antagonistic Genetic Blues

George De Stefano (July 23, 2008)
University of Padua researcher Andrea Camperio-Ciani

Researchers at the University of Padova think "sexually antagonistic" genes may influence male homosexuality


Italy, as I’ve previously noted in this blog, refuses to accept its gay sons and lesbian daughters as deserving of equal treatment and respect. In this respect it lags far behind the rest of Western Europe. But Italian scientists do like to study us. Now, a team of researchers at the University of Padova is claiming to have discovered a genetic mechanism that may be a “cause” of homosexuality.


Homosexuality in males may be caused in part by genes that also increase fertility in females, according to the study, which was reported in the June issue of the scientific journal PLoS ONE.


Andrea Camperio-Ciani, the evolutionary psychologist who led the research team, claims that the findings can explain why, if homosexuality is hereditary, it hasn't disappeared from the gene pool, since gay people are less likely to have children than heterosexuals.


Camperio-Ciani and his researchers found that female relatives of gay men have more children than average. The scientists used a computer model to explain how two genes – not one so-called “gay gene”-- passed through the maternal line could produce this effect.


Back in 2004 the researchers studied some 200 Italian families. They found that the mothers, maternal aunts and maternal grandmothers of gay men are more fruitful than average. The scientists needed a genetic model to make sense of the finding. After trying several, they found one that they claim works.


“This is the first time that a model fits all our empirical data,” said Camperio-Ciani. “These genes work in a sexually antagonistic way -- that means that when they're represented in a female, they increase fecundity, and when they're represented in a male, they decrease fecundity. It's a trait that benefits one sex at the cost of the other.”


Aside from whether the trait “costs” us gay men anything (I’m a happy non-breeder, so I beg to differ with Camperio-Ciani), the Padova team’s findings are intriguing, and they add a new element to the debate over the origins of sexual orientation. If the findings are confirmed by additional studies, they could help explain why, if homosexuality is indeed “caused” by genes, we homos don’t go extinct, given that we’re less likely to reproduce.


If the same genes contribute to homosexuality in men and increased fertility in women, then the bambini gay men don’t produce would be made up for by all those fecund mamme.


(Una domanda for the researchers: If these Italian women are so fertile, why is Italy’s birthrate so low? Well, at least it isn’t the queers’ fault.)


Although many researchers believe that homosexuality results from a mix of nature and nurture, they still can’t explain how the biological and the social might work together to produce a gay male or a lesbian female. And they’re really at a loss to explain why some people are attracted to both sexes.


Andrea Camperio-Ciani, though convinced he’s on to something, warns against making too much of his team’s findings. Even if the sexually antagonistic genetic system does the work he claims it does, it can only partly account for homosexuality in men. Camperio-Ciani says that other factors, both genetic and social, probably also play a part. Moreover, genetic sexual antagonism does not “explain” female homosexuality.


 “We're still working on lesbianism, but were not getting to the same result, and possibly we'll come out with a completely different explanation,” he said.




For some reason – oh, maybe the entire history of scientific and medical “interventions” concerning homosexuality – this makes me uneasy. I’m suspicious of all attempts to impute genetic causes to not only homosexuality but to any behavior or way of being that is outside the statistical or societal norm. The twentieth century showed us where biological determinism can end up, especially when it meshes with existing prejudices and social stigma. 


Why study the “causes” of homosexuality anyway? Because same-sex attraction and behavior is not statistically normative, and because of all the questions its non-normative nature raises, researchers are drawn to study homosexuality. (I feel compelled here to bring up the old gay liberation slogan – heterosexuality isn’t normal, just common.) But there’s a fine line between attempts to understand a phenomenon and efforts to wipe it out.


That’s why studies purporting to identify a biological cause are such a double-edged sword. Some gay advocates will use the research to claim our sexuality is innate and biologically determined so it cannot be either a sin or a “lifestyle choice.” But homophobes, who tend to have more power than gay people, will use the same findings to argue for medical interventions to cure what they see as a biological defect that produces “immoral” behavior.   


To his credit, Andrea Camperio-Ciani seems sensitive to these issues. He thinks his research can, in fact, undermine homophobia.


“I think this is an example where the results of scientific research can have important social implications,” he said. “You have all this antagonism against homosexuality because they say it’s against nature because it doesn't lead to reproduction. We found out this is not true because homosexuality is just one of the consequences of strategies for making females more fecund.”


Dr. Camperio-Ciani, please have a chat with Mara Carfagna. Perhaps you can talk some sense into Berlusconi’s Equal Opportunities minister, a dimwit who believes that gays deserve no legal protections because they are “constitutionally sterile.”  

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