That sounds really interesting, Sophist.
Is there any correlation with the brain gender of the fetus and estrogen levels in the mother's blood during pregnancy?
Completely missed this, Callaway, sorry.
I've not read anything focusing on estrogen levels in pregnant females, though it has been something I myself have wondered about. There may be the possibility of higher estrogen levels overall, or there could be typical estrogen levels but a decrease in the levels of progesterone (which is supposed to be higher during pregnancy) which has been shown to act like an antiestrogen in certain types of cells. It's unknown atm whether progesterone has antiestrogen-like effects on central nervous system tissue. But if it does, and if its levels are lower for some women during pregnancy than is typical, the typical or increased amounts of estrogen could have a greater effect with lesser progesterone opposition. For example, one study reviews steroidal effects on developing tissue:
"...low concentrations of a hormone can stimulate a tissue, while high concentrations can have the opposite effect. We report here that a 50% increase in free-serum estradiol in male mouse fetuses (released by a maternal Silastic estradiol implant) induced a 40% increase in the number of developing prostatic glands during fetal life; subsequently, in adulthood, the number of prostatic androgen receptors per cell was permanently increased by 2-fold, and the prostate was enlarged by 30% (due to hyperplasia) relative to untreated males" (vom Saal et al., 1997, p. 2056)
http://www.pnas.org/content/94/5/2056.abstract
So with a slight increased in estradiol stimulation, receptor numbers for androgens were double in adults as compared to controls. And, like I said, if progesterone acts as an antiestrogen-like cytokine in CNS tissue, then lower levels of progesterone could potentially increase the effects of estrogen without even increasing its actual blood levels.