Testing Biological Theories of Same-Sex Sexual Attraction and Transgender Identity: Somatic, Cognitive, Behavioural, and Demographic Markers

性别认同和性取向是两个最大的心理性别差异。绝大多数人都是顺性别（即，男性认同为男性，女性认同为女性）并表现出异性吸引力。然而，这些基本模式也有例外。相当多的少数人表现出同性的性吸引力和/或变性，因此，为研究大脑，认知和行为的性别差异提供了独特的人类模型。

Gender identity and sexual orientation are two of the largest psychological sex differences. The vast majority of people are cisgender (i.e., males identify as men, females identify as women) and exhibit opposite-sex attraction. Yet, exceptions to these fundamental patterns exist. Substantial minorities of people exhibit same-sex sexual attraction and/or transgenderism and, thus, provide unique human models for studying sexual differentiation of the brain, cognition, and behaviour.