Both sexual orientation and sex-typical childhood behaviors, such as toy, playmate and
activity preferences, show substantial sex differences, as well as substantial variability within …

Many people believe that sexual orientation (homosexuality vs. heterosexuality) is
determined by education and social constraints. There are, however, a large number of …

Testosterone plays an important role in mammalian brain development. In neural regions
with appropriate receptors testosterone, or its metabolites, influences patterns of cell death …

Sexual identity and sexual orientation are independent components of a person's sexual
identity. These dimensions are most often in harmony with each other and with an …

There is now good evidence that human sex-typed behavior is influenced by sex hormones
that are present during prenatal development, confirming studies in other mammalian …

During early development, testosterone plays an important role in sexual differentiation of
the mammalian brain and has enduring influences on behavior. Testosterone exerts these …

Experiments in animals leave no doubt that androgens, including testosterone, produced by
the testes in fetal and/or neonatal life act on the brain to induce sex differences in neural …

Convincing evidence indicates that prenatal exposure to the gonadal hormone,
testosterone, influences the development of children's sex-typical toy and activity interests. In …

We review research supporting biological mechanisms in the development of sexual
orientation. This research includes studies on neural correlates, prenatal hormones and …

Male and female fetuses differ in testosterone concentrations beginning as early as week 8
of gestation. This early hormone difference exerts permanent influences on brain …