Several studies have attempted to determine what the structural differences are in transsexual brains.
Gooren's 1990 review discussed differences in brain development on fetuses exposed to unusual hormonal environments.
Zhou et al (1995) found that the central subdivision of the bed nucleus of the stria terminalis (BSTc) was smaller in men than in women, and found that in the six male-to-female transsexuals they examined (regardless of hormone treatment history), this same area was of a female size. In a follow-up article five years later,
Kruijver et al (2000) (including Zhou) found more similarities between cisgendered female and MTF-transsexual BTSc, using the same sample as in 1995, plus 16 new brains
I've been avoiding this topic. I've been asked about when it will hit Difference Blog (and about other transsexual topics) and I tend to mumble and look the other way. I don't think it's important, I don't like the way it's handled., and I'm generally unimpressed with the science. But mostly, I avoid it because Difference Blog is not about transsexuals, but about the differences between otherwise matched men and women.
Besides: the way I look at it, if I'm not going to let a piece of flesh several inches long determine how I'm going to live my life, why would I let a piece of brain a couple of millimeters across do it?