You seem to have an interest in scientific articles. Here is one which appears in the NCBI.NLM.NIH.gov database. The title of the article is Androgen Receptor Repeat Length Polymorphism Associated With Male-To-Female Transsexualism. The science and terms are somewhat complex, but the conclusion is easy to understand. I am quoting just a snippet out of the Discussion section. It was published over 13 years ago, but the findings are still valid. Further research in this area has just reinforced the original conclusion.
“To date, this is the largest genetic study of transsexualism conducted. We observed a significant association between longer AR gene polymorphisms and male-to-female transsexualism. Longer CAG repeats in the AR gene lead to reduced binding of the AR protein to co-activator, due to its inhibitory interaction with the receptor, resulting in less effective testosterone signalling (19), a mechanism typically involved in masculinization of the brain during early development (1). Female subjects typically lack the gonadal testosterone surge that occurs in male subjects. Consequently, the AR gene is not activated (20). 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.”
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“In conclusion, our findings indicate a significant association between male-to-female transsexualism and the long polymorphism for the AR repeat. This finding links the androgen receptor and further implicates genes in the steroidogenesis pathway as playing a role in male-to-female transsexualism. We speculate that reduced androgen and androgen signalling might contribute to the female gender identity of male-to-female transsexuals. Further studies including replication in other populations, larger patient collections, and analysis of other polymorphisms, both for the genes studied here and other sex steroidogenesis genes, should be undertaken.”
You can find this and other articles by doing a Google search for Difference between male and female AR gene.
