Male transsexual gene found.

From BBC:

Australian researchers have identified a significant link between a gene involved in testosterone action and male transsexualism.

DNA analysis from 112 male-to-female transsexual volunteers showed they were more likely to have a longer version of the androgen receptor gene.

The genetic difference may cause weaker testosterone signals, the team reported in Biological Psychiatry.

However, other genes are also likely to play a part, they stressed.

Increasingly, biological factors are being implicated in gender identity.