Hi Coptic,
(1) That’s a far cry from your original claim that such studies are worthless.
(2) If the differentiation happens in adulthood, not in childhood… So what? My point that transsexuals have brain structure matching their mental identity, not their physical identity still stands. When and why that happens is secondary. We’re looking at ontological implications of this.
(3) If the study in question did not correctly control for hormone intake, then we are still left with a conclusion that hormone levels can influence brain structure (and why wouldn’t they, if sexual differentiation in humans is hormone-driven?). This would be a very powerful finding anyway. It would imply two things: (a) an individual with messed-up hormonal balance will grow up transsexual; (b) by undergoing a hormone therapy, a person actually rewires his/her brain to a target gender.
Anyway, I’m going to return to the point made by the OP. From what we know so far, an individual’s sexuality has several dimensions:
(a) genotype (XX/XY)
(b) phenotype (male/female)
(c) self-perceived gender (male/female)
(d) object of sexual attraction (males/females)
Now, the most typical combinations are:
- man: XY, male phenotype, male ego, female-attracted
- woman: XX, female phenotype, female ego, male-attracted
Problem is, these are not the only combinations possible, and specifically, an individual
cannot in general be classified simply as a man/woman basing on one parameter alone. Yes, it will work for
most people, but not for all. To wit:
- XX/XY differentiation is not enough. Example: CAIS – an XY female (albeit sterile).
- phenotype itself is not enough. Examples: (1) CAIS; (2) Gender Identity Disorder.
- self-perceived gender is not enough. As you have noted, other people will not agree with individual’s self-identification, and can react quite violently after finding that individual’s phenotype does not neet their expectations.
- object of sexual attraction. Homosexuality, enough said.
That’s why I believe that two ontological errors should be avoided:
(1) reducing individual to XX/XY type. It’s incorrect, reductionist and materialist.
(2) lumping together transsexuality and homosexuality. As most homosexuals have no symptoms of GID, there’s good reason to believe that both disorders are unrelated (although one may be misdiagnosed as the other).