Human sexuality is not determined by a single ‘gay gene’, study finds

HUMAN sexuality is not determined by a single “gay gene”, a study shows.

Scientists identified five significant differences in people’s DNA linked to bi- or homosexuality.

But these collectively account for just 1 per cent of the odds of being attracted to the same sex.

The researchers say thousands more genetic variations appear to be involved.

But it is thought these could only ever increase the predictive power of a genetic test to 25 per cent.

It suggests the environment in which somebody is raised plays a bigger role in determining sexuality.

The Institute of Molecular Medicine, in Finland, analysed the genomes of more than 477,000 people.

THOUSANDS OF VARIATIONS

They found thousands of variations potentially linked to same-sex sexual behaviour and proved five.

These variations also appear to affect an individual’s sex hormones and sense of smell.

From 2 to 10 per cent of people report being attracted to the same sex, either exclusively or in addition to the opposite sex.

Study leader Dr Andrea Ganna said: “Same-sex sexual behaviour is influenced by not one or a few genes but many.”

Commenting on the study, Prof Melinda Mills, from the University of Oxford, described the established effects as “small”.

She added: “The effects are so small that this genetic score could not be reliably used to predict same-sex sexual behaviour of an individual.

“Using these results for prediction, intervention or a supposed ‘cure’ is wholly and unreservedly impossible.”

The findings are published in the journal Science.

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