Gene linked to transsexualism

A variation in the gene involved in testosterone action has been linked to male transsexualism, in the largest ever genetic study of male-to-female transsexuals.

DNA analysis of 112 male-to-female transsexuals has shown a genetic differentiation in the androgen receptor for testosterone may go some way to explaining transsexualism, scientists from Melbourne’s Prince Henry’s Institute have reported in Biological Psychiatry.

Male-to-female transsexuals were more likely to have a longer version of the androgen receptor for testosterone, which could impede the hormone’s function. Researchers speculated that the reduction in male hormones could lead to the development of a more female brain during foetal development, which could explain why many transsexuals feel a sense of difference from an early age.

There is a social stigma that transsexualism is simply a lifestyle choice, however our findings support a biological basis of how gender identity develops, said study leader, Associate Professor Vincent Harley.

Professor Sinclair of the University of Melbourne agreed that the study opened up new avenues for exploration but was careful to point out that the findings were not necessarily applicable to all.
These defective copies of the AR gene could severely reduce normal testosterone levels, resulting in a more female brain. Consequently, male-to-female transsexuals might be expected to have a more feminised brain and are therefore likely to display a female gender identity.

This supports the notion that transsexualism has a biological, genetic basis rather than being due to psychosocial factors in early childhood. However, this finding does not explain all male-to-female transsexuals suggesting that multiple genetic factors are involved.

University of New South Wales Associate Professor in Sexual Health, Juliet Richters agreed.
The results of this study do not look like the kind of overwhelming association you find when you’re onto the main cause of something, so it seems likely to me that this sex steroid-producing gene may in some way be linked to sexuality or features of gender behaviour, but is far from determinative of transsexualism, Richters said.

We must remember that much of the distress experienced by male-to-female transsexuals is not caused simply by the sense of -˜being in the wrong body’ but by the stigmatising and frankly cruel way in which people often treat those who do not conform to expectations of socially appropriate gendered behaviour.

It may be a matter of relief for transsexuals to have their condition identified as genetic, rather than being blamed for an awkward -˜lifestyle choice’. But a little more tolerance towards everyone who doesn’t conform to gender norms would be a good thing.