In other words, given the size of a particular INAH3, it would be impossible to predict into which sexual orientation group a subject would fall. Rodents have provided much of the information used to construct the current biological model of human sexuality. There is no evidence that androgens have these effects in humans. The arguments are explained in greater detail below. To a large extent, male and female rats do have different stereotypic reproductive behaviors which can be altered by varying levels of androgens during development.
Male rats tend to mount other rats more than do female rats.
These effects of androgen levels on reproductive posture and motor behavior in rats form the basis of theories on human homosexuality. Adult male rats who have been exposed to androgens secreted from their own testes during development cannot release a surge of LH in response to administered estrogen. In addition, female rats exposed to experimentally induced high levels of androgen during their development will not have an LH surge in response to estrogen. In other words, the after exposure to high levels of androgens during fetal development, the hypothalamus no longer has the ability to mediate the positive feedback of estrogen. Androgen exposure has a permanent effect on the hypothalamus.