ABSTRACT
It is clear that arguments that being gay or transgender or engaging in non-reproductive sex acts is ‘against nature’ are sadly uninformed. Diversity suggests that sex and gender variance may be useful and functional, that is, serve a purpose in perpetuating the species. The fundamental question addressed by causality/etiology research is: how much is sexual orientation determined by innate, inborn factors, and how much by learned, environmental factors? There is evidence both for genetic factors and for non-social environmental factors like birth order or pre-natal hormonal exposure in the etiology of same-sex attraction. None of these factors are found in all same-sex-oriented people, leaving room for other environmental factors to play a role in the formation of sexual orientation. The early psychoanalytic theories of the origins of homosexuality in family dynamics seem to be thoroughly debunked by science.
