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

测试同性性吸引力和变性身份的生物学理论：躯体、认知、行为和人口标记

• 批准号: RGPIN-2016-06446
• 负责人: VanderLaan, Doug
• 金额: $ 2.4万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616313
• 关键词: Testing; Biological; Theories; Same; Sex

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. Hormonal, genetic, and immunological processes have been hypothesized to influence sexual differentiation of the brain and lead to within-sex variation in gender identity and sexual orientation. Previous research examined whether somatic, cognitive, behavioural, and demographic markers of these biological processes differentiate transgender vs. cisgender individuals on the one hand, and same- vs. opposite-sex attracted individuals on the other. Biomarkers associated with transgenderism are often also associated with same-sex sexual attraction. Yet, because no studies directly compared these biomarkers across same-sex attracted cisgender vs. transgender individuals, it is unclear to what extent, if any, these two phenotypes are underpinned by different biological processes. To clarify this issue, one must examine a population in which comparing groups of same-sex attracted cisgender vs. transgender individuals is feasible. In Western countries, transgenderism is rare and difficult to study outside of specialty clinics. Hence, the proposed research will be situated in Thailand where cisgender same-sex attraction is relatively common (2-5%) and, due to a lack of social censure regarding gender expression, transgender same-sex attraction is 50 to 250 times more common than in other populations. Thus, the Thai population provides a rare opportunity to compare same-sex sexual orientation and transgenderism as human models of sexual differentiation. Thai same-sex attracted cisgender vs. transgender individuals will be compared on a comprehensive set of relevant biomarkers. These include several markers linked to prenatal androgen exposure: brain structure (e.g., cortical thickness, white matter microstructure), second-to-fourth digit ratio, physical size (e.g., height, weight), face structure, cognitive abilities (e.g., mental rotation), and behavioural characteristics (e.g., handedness). To provide insight regarding genetic and immunological factors, familiality of transgenderism and same-sex sexual orientation and participants’ birth orders will be examined, respectively. By comparing same-sex attracted cisgender vs. transgender individuals on a comprehensive set of biomarkers, my research program will transform our understanding of how these respective human models and biomarkers shed light on sexual differentiation of the brain, cognition, and behaviour.

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（即男性认为是男性，女性认为是女性），但这些基本模式也存在例外。绝大多数人表现出同性性吸引力和/或跨性别主义，因此为研究大脑、认知和行为的性别分化提供了独特的人类模型。 荷尔蒙、遗传和免疫过程已被用来影响大脑的性别分化，并导致性别认同和性取向的性别内差异。先前的研究探讨了这些生物过程的躯体、认知、行为和人口特征是否能够区分跨性别者。一方面是同性吸引个体，另一方面是同性吸引个体与异性吸引个体。与跨性别相关的生物标志物通常也与同性性吸引力相关。性吸引顺性别与跨性别者相比，目前尚不清楚这两种表型在多大程度上（如果有的话）受到不同生物过程的支撑。 为了澄清这个问题，我们必须检查一个人群，在其中比较同性吸引的顺性别者和跨性别者群体是可能的，在西方国家，跨性别现象很少见，并且很难在专业诊所之外进行研究。位于泰国，顺性别同性吸引相对常见（2-5%），并且由于缺乏对性别表达的社会谴责，跨性别同性吸引比其他人群常见 50 至 250 倍。泰国人口提供这是一个难得的机会，可以将同性性取向和跨性别主义作为人类性别分化模型进行比较。 泰国同性吸引的顺性别者与跨性别者将在一组全面的相关生物标志物上进行比较，其中包括与产前雄激素暴露相关的几个标志物：大脑结构（例如，皮质厚度、白质微观结构）、第二至第四位数字。比例、身体尺寸（例如身高、体重）、面部结构、认知能力（例如心理旋转）和行为特征（例如惯用手）提供有关遗传和免疫因素的见解，将分别检查跨性别和同性性取向的家族性以及参与者的出生顺序。 通过在一组全面的生物标志物上比较同性吸引的顺性别者和跨性别者，我的研究项目将改变我们对这些各自的人类模型和生物标志物如何揭示大脑、认知和行为的性别分化的理解。