You say no transwomen believe this, it has been called a riddiculous straw man.  Yet if one goes to tsroadmap.com and/or lynnconway.com and googles (in the search boxes you would see on their pages) "brain sex" they will get many hits.    Read "The theory that prenatally established brain and CNS   structures determine innate gender feelings and gender identity."  "It appears that if those brain and CNS structures are masculinized   in early pregnancy by hormones in the fetus, then the child will   have male percepts and a male gender identity, independent of   whether the genes or genitalia are male. If those structures   are not masculinized in early pregnancy, the child will have   a female percepts and a female gender identity, again independent   of the genes or genitalia. As in the case of intersex infants   having ambiguous genitalia, there are undoubtedly many degrees   of cross-gendering of brain and CNS structures, so that while   some infants are completely cross-gendered others are only partially   cross-gendered.(verbatim)"  This is basically the feminine essence theory. When one adds that there is only one way to be cross-gendered in the brain, and that cross gendering must be totally separate in any and every way from sexualorientation. That there is in essence one way to be feminine; that is the feminine essence theory.

Interestingly if I understood JamesCantor correctly in a conversation we had on my talk page.  This is very close to what he and sexologist like him belive. However they contend that the way in which a brain is cross-gendered depends on sexualorientation.  Thus take a homosexual male.  Homosexual males have been shown to think and have some brain structures like those of straight women.  A homosexual transsexual is just a case where there is more enough female brain structure present to make a person mentally female.  While non-homosexual transsexuals, if I understood correctly, also have cross gender structures in their brains, just not the same as a homosexual transsexuals.  The non-homosexual MTF transsexual brains retaining more masculine brain structure.  That is the crux of the problem isn't it now.  That Blanchard's theory not only contradicts the feminine essence/ female brain sex theory of MTF transsexualism....but it then says ok one kind of transsexual really does work that way.  So much heat and anger caused by so little.  -(