Deprivation of testosterone or estrogen during fetal development can prevent the emergence of brain circuits responsible for sexual behavior.

“We now know that there are connections in the female brain that are simply missing in the male brain and these connections are from neurons that regulate sexual behavior. So we know that some circuits are missing in the male brain for sexual female sexual behavior.”

“Um, and early on in development, at embryionic stages in some species, um, like in humans, in in uterro, uh, when the, you know, when the woman's pregnant or in mice just at birth, perinatally, just after birth, um, these hormones generate what is thought to be an irreversible differentiation of the brain along a female or a male pathway.”