Gender differences and sexual orientation in the brain

From the Beeb and several other sources comes an article about which I already kind of knew the answer:

Homosexual brains are similar to heterosexual brains of the opposite sex.

The survey was different, though, in that it measured hemisphere volume. Lesbians and heterosexual men had asymmetric hemispheres, while gay men and heterosexual women had symmetric hemispheres.

What this says about people who are bisexual or pansexual or who are transgender or who are intersex, I don't know. Nature, however, is not quite as cut-and-dry as to make a clear-cut dichotomy for sexual orientation and sex, even though individuals on neither end of the dichotomy don't appear often, so this study has some flaws, but that's another post.

Most studies I've seen about this have been mostly about hormones, in which lesbian women have elevated levels of testosterone and gay men have elevated levels of estrogen or where lesbian women have more or less activation in a certain area of their brain or where gay men have more or less activation in a certain area of their brain than heterosexual people of their sex. What we do know is that sexual orientation is biological.

There are also differences in symmetry of synaptic junctions in the amygdala.

What I'd like to see is a study on people who fit neither end of one or both of the continua to see how similar a brain in, say, a bisexual or pansexual person is to heterosexual or homosexual people.

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