An Evolutionary Biodevelopmental Neuroscience of Same-Sex Sexual Orientation and Transgender Identity

我的研究计划旨在实现一门关于性取向和性别多样性的综合进化生物发育神经科学。同性性取向(相对于出生分配的性别)被认为受到适用于所有人口的生物过程的影响，表现为顺性(顺性别；即性别认同/角色和出生分配的性别一致)或变性人(跨性别者，即性别认同/角色和出生分配的性别不一致)。这项拟议的研究由三个项目组成，旨在检验同性性取向的顺式和反式表达具有不同的生物学基础的假设。研究设计的一个关键方面是这些项目是在泰国进行的。鉴于之前关于同性性取向生物学的大部分工作都集中在西方人群，对泰国参与者的研究为影响性取向的生物过程适用于整个人群这一观点提供了强有力的测试。此外，由于泰国对性别和性别多样性的能见度和社会接受度很高，这是少数几个可以招募足够大的顺位和跨性别者样本进行严格研究的人群之一。项目1测试了几个关于同性性取向的生物发展和进化的个人假设。具体地说，它包括检查遗传、激素和免疫过程的标记，这些标记被认为是同性性取向生物发育的基础。它还测试了关于同性性取向的两个进化论假说：亲缘关系和平衡选择。项目2评估了同性被吸引的亚群的可能存在。据预测，遗传、荷尔蒙和免疫过程都适用于同性吸引的一小部分人。根据先前的研究，预计这些亚群将通过性别表达来划分，不同的亚群将显示出不同的进化起源的证据。项目3测试了生物过程通过对大脑性别分化的影响来影响性取向和性别认同的想法。因此，该项目比较了大脑结构的性别差异方面(即皮质厚度和表面积、白质微结构)与性别、性取向和性别认同的关系。该项目还将探索大脑-生物发育-进化之间的联系。这些项目将共同阐明性取向和性别多样性的生物学基础。在这样做的过程中，他们还将让人们了解大脑和行为的性别分化。此外，这项研究计划将为高素质的人员提供独特的培训机会，并为如何整合进化论、生物发育和神经科学以实现对复杂心理特征的全面理解提供一个模式。

My research program aims to achieve an integrated evolutionary biodevelopmental neuroscience of sexual orientation and gender diversity. Same-sex sexual orientation (relative to birth-assigned sex) is thought to be influenced by biological processes that apply across populations and is expressed as either cisgender (cis; i.e., gender identity/role and birth-assigned sex align) or transgender (trans; i.e., gender identity/role and birth-assigned sex do not align). The proposed research consists of three projects designed to test the hypothesis that cis vs. trans expressions of same-sex sexual orientation have distinct biological bases. A critical aspect of the research design is that these projects are conducted in Thailand. Given most prior work on the biology of same-sex sexual orientation focused on Western populations, examining Thai participants provides strong tests of the idea that biological processes influencing sexual orientation apply across populations. Moreover, due to the high visibility and social acceptance of sexual and gender diversity in Thailand, it is one of the few populations in which it is feasible to recruit sufficiently large samples of cis and trans same-sex attracted individuals for rigorous studies. Project 1 tests several individual hypotheses regarding the biodevelopment and evolution of same-sex sexual orientation. Specifically, it consists of studies that examine markers of genetic, hormonal, and immune processes thought to underpin same-sex sexual orientation biodevelopment. It also tests two evolutionary hypotheses regarding same-sex sexual orientation: kin and balancing selection. Project 2 evaluates the possible existence of same-sex attracted subgroups. Genetic, hormonal, and immune processes are predicted to each apply to a subgroup of same-sex attracted individuals. Based on prior research, it is expected that these subgroups will be delineated by gender expression and that different subgroups will show evidence of distinct evolutionary origins. Project 3 tests the idea that biological processes influence sexual orientation and gender identity via their impacts on sexual differentiation of the brain. Thus, this project compares sex-differentiated aspects of brain structure (i.e., cortical thickness and surface area, white matter microstructure) in relation to sex, sexual orientation, and gender identity. This project will also explore brain-biodevelopment-evolution links. Together, these projects will elucidate the biological bases of sexual orientation and gender diversity. In so doing, they will also inform understanding of sexual differentiation of the brain and behaviour. In addition, this program of research will furnish unique training opportunities for highly qualified personnel and provide a model for how to integrate evolution, biodevelopment, and neuroscience to achieve comprehensive understanding of complex psychological traits.