A recent study shows there is no one gene that determines homosexuality, but confusion still lingers on the predictive power of our genetic constitution. Far more interrogation is needed before the discussion reflects the reality of what genes "do"by Philip Ball / September 4, 2019 / Leave a comment
Some people once felt that the reason to look for a “gay gene” was so that it could be eliminated. Under the headline “Abortion hope after ‘gay genes’,” in 1993 the Daily Mail wrote “Isolation of the genes [causing homosexuality] means it could soon be possible to predict whether a baby will be gay and give the mother the option of an abortion.”
Revisiting that reporting now it has been announced that there is no “gay gene” shows us how much has changed over less than three decades in public attitudes to homosexuality. Sadly, there has not been a comparable change in public attitudes to genes. Few would now take the abhorrent view that a genetic propensity to being gay would constitute good grounds for termination of a pregnancy, but probably many would have no problem believing that your genes could “make you gay” in the first place. This latest interrogation of genetic determinism illustrates how far we have still to go to shift the prevailing narrative about genes.
The new research, led by a team at the Broad Institute of Harvard University and the Massachusetts Institute of Technology, combed the genomes of nearly half a million people, using data from the UK’s Biobank repository of biomedical data, supplemented by that provided (with consent) by the American gene-sequencing company 23andMe. The researchers looked for correlations between genetic profiles and sexual orientation as reported by participants in the survey.
What they found takes some unpacking. First, there are some common features in the genes of people who self-report as being gay or attracted to the same sex: the researchers estimate that as much as 25 per cent of sexual behaviour could be explained by genetics. Second—this might at first seem to contradict that claim—one can’t, on the basis of these results, make any meaningful prediction about someone’s sexual orientation from their genome.
To unravel what all this means, we should first recognise that most if not all of our behavioural traits are influenced by our genes to some degree. It has long been known that the probability of a person being gay has an inherited component. In fact, comparisons of people’s genetic profiles have shown that there are statistical similarities in the genes of people who get divorced, watch a lot of television, engage in criminal activity—you name it.
At face value this seems…