Prof. Pedro Jurberg, PhD - neurobiologist from Fundação Oswaldo Cruz - Rio de Janeiro - Brazil and I - Dr.Torres, MSc, PhD, during the year of 2000-2001, studying transsex, we proposed the named Torres & Jurberg hypothesis for a possible genetic (receptors based) cause for MtF transsex (not always but at least sometimes):

• 1. Gender Identity is a development that has as its core part, the brain;



• 2. Inside the brain, the core part is the basal "reptilian" brain, including hypothalamus, stria terminalis, amygdalas and limbic system, among other possible parts;



• 3. A lot of studies with primate species, including humans but non-humans mainly, showed the sex differentiation of these basal brain structures, were mainly determined by the action of testosterone (T) and not Di-hydro-testosterone (DHT);



• 4. There is also plenty of evidence that the sexual tissues (genital tissues also), are derived NOT FROM THE ACTION OF TESTOSTERONE DIRECTLY, but by the action of DHT;



• 5. So, we proposed a hypothesis, and a study program to develop it - but with no help in Brazil or abroad;



• 6. As genital tissues are determined by DHT action, and the basal brain is determined by T action - they could develop in discord;



• 7. All studies of T action in the brain in primates - humans and non-humans, shows some very interesting things;



• 8. As in genital tissues, the cortical brain is differentiated by DHT, during and mainly after gestation, in primates;



• 9. But it was discovered even in the 80's of the past century that in primates, the basal brain areas are differentiated by T and not DHT;



• 10. We know also that DHT works by acting on AR-the androgen receptors directly;



• 11. We know also very well that T is much more complex, and acts over AR and ER - the estrogen receptors, due to a process named aromatization;



• 12. So we concluded then that a problem with the AR would cause problems for T and DHT;



• 13. Any ER problem would trigger problems over T action, and not necessarily DHT;



• 14. There is a lot of knowledge about AR problems, we label AR insensitivity syndromes (AIS);



• 15. Among AIS there are complete (CAIS), partial (PAIS) and minimum or mild (MAIS);



• 16. Our Torres & Jurberg hypothesis considered the probability of some TS MtF situations being related to MAIS insensitivities.
• 17. Since 2000 we have not had the opportunity to test that hypothesis;



• 18. We presented our paper at the 15th World Congress of Sexology in Paris, 2001. Then only an abstract was published at the Annals.




To read our Torres & Jurberg original paper, click here