Biology and sexual orientation INAH3 weight for the heterosexual male brains was significantly larger than for the heterosexual female brains, while the results for the gay male group were between those of the other two groups but not quite significantly different from either. The neuron count also found a male-female difference in INAH3, but found no trend related to sexual orientation. A 2010 study, Garcia-Falgueras and Swaab asserted that "the fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge.
Sexual desire and intimate relationships primary goal of sexual desire. It has also been suggested that women are more likely than men to develop a “relational” or “person-centered” orientation to sexual desire, whereas men are more likely to adopt a “recreational” or “body-centered” orientation to sexuality. These results further support the suggestion that despite generally consistent definitions of sexual desire, perceived differing end goals of sexual desire may exist between the sexes. In keeping with providing definitions of sexual desire consistent with those of theorists, both men and women have consistently expressed their beliefs that the causes of male sexual desire differ from female causes