Friday, 12 March 2010
Garcia-Fulgeras and Swaab.
Zoe Brain
http://aebrain.blogspot.com/2010/03/garcia-fulgeras-and-swaab.htmlFrom Latest and Greatest from two of the big names in the Science of Sex and Gender : Garcia-Fulgeras and Swaab.
Sexual Hormones and the Brain: An Essential Alliance for Sexual Identity and Sexual Orientation Garcia-Falgueras A, Swaab DF Endocr Dev. 2010;17:22-35
The fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. In this way, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation are programmed or organized into our brain structures when we are still in the womb. However, since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in extreme cases in trans-sexuality. This also means that in the event of ambiguous sex at birth, the degree of masculinization of the genitals may not reflect the degree of masculinization of the brain. There is no indication that social environment after birth has an effect on gender identity or sexual orientation.
Note though that - Bisexuals may have an apparent change of sexual orientation, and the Bigendered may have an apparent change of gender identity (though I wish they'd call it sex identity). It's neither a strict binary, nor a strict trinary.
