Transgender Organizations
Transsexual, Transgenderist, Cross-Dresser support and social groups, activist Organizations  
Napa Valley, San Francisco North Bay, Ca. USA

Some recent findings have provided clues and possibly answers as to how or why some or most cases of transsexuality occur. In 1997, J.N. Zhou, M.A. Hofman, L.J. Gooren and D.F. Swaab conducted tests on the brains of transgender individuals. Their tests showed that the volume of the central subdivision of the bed nucleus of the stria terminalis (BSTc), a brain area that is essential for sexual behaviour, is larger in men than in women. A female-sized BSTc was found in male-to-female transsexuals. The size of the BSTc was not influenced by sex hormones in adulthood and was independent of sexual orientation. Their study was the first to show a female brain structure in genetically male transsexuals and supports the hypothesis that gender identity develops as a result of an interaction between the developing brain and sex hormones. Perhaps confirming why this brain difference occurs, in 2008 at Prince Henry's Institute of Medical Research in Melbourne, biological studies were performed to attempt to find a link between genes and transsexuality. Their study shows male to female transsexuals are more likely than non-transsexual males to have a longer version of a receptor gene for the sex hormone androgen or testosterone. The research suggests reduced androgen and androgen signaling contributes to the female gender identity of male to female transsexuals. They say that it is possible that a decrease in testosterone levels in the brain during development might result in incomplete masculinization of the brain in male to female transsexuals, resulting in a more feminized brain and a female gender identity