Genetic link to transexuality 'discovered'

Washington (PTI): For decades, there has been debate over the causes of transexuality. Now, researchers have discovered a significant genetic link between gender identity and a gene involved in testosterone action.

From an early age people develop an inner sense of being male or female -- their gender identity. Transsexuals however, identify with a physical sex opposite to their perceived biological sex.

For the study, an international team collected DNA samples from 112 male to female transsexuals and then compared genetic differences with non-transsexuals.

The researchers discovered that male to female transsexuals were more likely to have a longer version of a gene which is known to modify the action of the sex hormone testosterone, the 'Biological Psychiatry' journal reported.

"We think that these genetic differences might reduce testosterone action and under masculinise the brain during foetal development," said lead researcher Lauren Hare.

Added co-researcher Professor Vincent Harley of Prince Henry's Institute: "There's social stigma that transsexualism is simply a lifestyle choice, however our findings support a biological basis of how gender identity develops. As with all genetic association studies, it will be important to replicate these findings in other populations."

The researchers are now planning even larger genetic studies and are investigating a wider range of genes that may be related to gender identity.