Another piece of the puzzle

[Shana A]

Tuesday, 11 November 2008
Another piece of the puzzle
Zoe Brain

http://aebrain.blogspot.com/2008/11/another-piece-of-puzzle.html

Perhaps a "tipping point" has been reached now, with more and more data clarifying the situation, and confirming theory.

Professor M.Italiano of Gendercare Inc. and Organisation Intersex International (to whom many thanks) very kindly sent me an advance copy of a new article, whose abstract is available from Oxford Journals.

From A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity by
A. Garcia-Falgueras A and D.F. Swaab.

    In the present study we investigated the hypothalamic uncinate nucleus, which is composed of two subnuclei, namely interstitial nucleus of the anterior hypothalamus (INAH) 3 and 4. Post-mortem brain material was used from 42 subjects: 14 control males, 11 control females, 11 male-to-female transsexual people, 1 female-to-male transsexual subject and 5 non-transsexual subjects who were castrated because of prostate cancer.
    ...
    We showed for the first time that INAH3 volume and number of neurons of male-to-female transsexual people is similar to that of control females. The female-to-male transsexual subject had an INAH3 volume and number of neurons within the male control range, even though the treatment with testosterone had been stopped three years before death. The castrated men had an INAH3 volume and neuron number that was intermediate between males (volume and number of neurons P > 0.117) and females (volume P > 0.245 and number of neurons P > 0.341). There was no difference in INAH3 between pre-and post-menopausal women, either in the volume (P > 0.84) or in the number of neurons (P < 0.439), indicating that the feminization of the INAH3 of male-to-female transsexuals was not due to estrogen treatment. We propose that the sex reversal of the INAH3 in transsexual people is at least partly a marker of an early atypical sexual differentiation of the brain and that the changes in INAH3 and the BSTc may belong to a complex network that may structurally and functionally be related to gender identity.