Sexual differentiation of the human brain in relation
to gender identity and sexual orientation.
Ivanka Savic, Alicia Garcia-Falgueras and Dick F. Swaab
Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences,Amsterdam, The Netherlands
Medical Psychology Unit, Institute of Neuroscience, Autonomous University of Barcelona, Bellaterra, Barcelona, Spain
Gender developement of the fetal brain.
How it is possible for a individual to be born as a Transsexual Male or Female ... born with the presenting body of one gender and the brain of the opposite gender. As in example a person born presenting physically as a male but has the brain or parts of the brain of a female. .
Abstract
It is believed that during the intrauterine period the fetal brain develops 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. According to this concept, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation should be programmed 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 transsexuality. 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 proof that social environment after birth has an effect on gender identity or sexual orientation. Data on genetic and hormone independent influence on gender identity are presently divergent and do not provide convincing information about the underlying etiology. To what extent fetal programming may determine sexual orientation is also a matter of discussion. A number of studies show patterns of sex atypical cerebral dimorphism in homosexual subjects. Although the crucial question, namely how such complex functions as sexual orientation and identity are processed in the brain remains unanswered, emerging data point at a key role of specific neuronal circuits involving the hypothalamus.
Researched and Posted by
Michelle Lynn GreyFeather
Identifying as Bi Gender
The Transology Association
A Non Profit Transgender Support and Educational Organization
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