We propose that in humans this mechanism may contribute to the relationship between non-heterosexual orientation and increased prevalence of neuropsychiatric disorders.
We show that pharmacological or genetically induced changes in neurotransmitter systems during development might, by hormone-mediated structural and functional brain changes, result in alterations in sexual preference in animal models. In this article, we review the evidence from basic research on the possible role of neurotransmitters on influencing sexual orientation. According to the neuro-hormonal theory, sexual orientation in humans develops in the womb under the influence of sex hormones.