By Tim SpectorFeb. 18, 2014, 10:13 p.m.

Why does a "gay gene" paper still cause a stir? A similar paper on any other topic would probably have passed unnoticed. But this is sex research where public interest is huge but real funds and real science are very scarce and stories get recycled.

Why does a "gay gene" paper still cause a stir? A similar paper on any other topic would probably have passed unnoticed. But this is sex research where public interest is huge but real funds and real science are very scarce and stories get recycled.

A study which is not even yet a paper was presented in preliminary form on Valentine's Day by sex researcher Mike Bailey at a conference in Chicago saying that there is a genetic component to homosexuality. In fact, their study of 400 pairs of brothers, where at least one was gay, confirmed a smaller controversial study from 20 years before, and several twin studies in between. The 1993 study led the Daily Mail to run one of its most infamous headlines: "Abortion hope after gay genes finding".

The Bailey paper claims to have found large segments of chromosomes containing hundreds of genes that are common in gay men. The researchers admitted they couldn't find any specific "gay genes".

Last year, a paper in a relatively obscure journal also caused a public stir for saying just the opposite. The authors came up with a complicated biological explanation for why gay men have more female relatives, tend to have older brothers and why it involves testosterone in the womb and runs in families. Controversially, they said it wasn't due to their genes, but to small chemical signals that alter the genes (called epigenetics) which can pass from one generation to the next, and had some (unclear) evolutionary advantage.

The study was undoubtedly clever and involved high-powered maths, but was purely theoretical, didn't involve real people and made false assumptions leading to fatal flaws.

This latest round of reporting following the Bailey research has led to perhaps inevitable criticism that we have an obsession with male homosexuality.

One reason people react so violently to these studies is a lack of understanding of basic biology and science, and realising that homosexuality is for a scientist just another human characteristic or trait, like sporting ability, obesity, optimism or depression.

Almost all human traits studied have some genetic (heritable) component, usually in the range of 30-70 per cent. Homosexuality in males and females has a heritability in most studies of around 30-40 per cent with plenty of room for environment. And there is no single gene for any of these traits.

Read more:
Gay genetics research still causes irrational fears

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