Psychology of Sexual Orientation and Gender Diversity, Vol 12(3), Sep 2025, 379-391; doi:10.1037/sgd0000671
Historically, scientific studies have searched for a “cause” of transgender identity, focusing on prenatal androgen exposure. Participants are usually recruited from gender clinics and correlations are sought between biomarkers and gender identity, often with inconsistent results. We evaluated this approach by examining the utility of two commonly used biomarkers, digit ratio and mental rotation tasks, using community-based recruitment that included both transgender and nonbinary identities, unlike previous research. Participants (N = 1,200) were asked to describe their identities using both self-labeling and gender and sexual orientation scales, took a mental rotation test, and had their hands scanned for digit ratio measurement. We found that digit ratio and mental rotation scores were consistent with sex assigned at birth rather than gender identity, using both categorical gender groupings and continuous gender scales. We also found no evidence supporting the historical typology of “homosexual” and “nonhomosexual” groupings of transgender individuals. In addition, we found that 32% of transgender women (n = 168) and 45% of transgender men (n = 175) experienced changes in their sexual orientation with gender transition and, at least for transgender women, there was an increased chance of a change in sexuality among those using hormones. Finally, our data suggest an interaction of race/ethnicity with how sexuality is experienced and/or reported by transgender women. These results highlight the importance of taking an inclusive, community-based approach and call for an examination of underlying assumptions and measures used to explore the development of gender identity and sexual orientation. (PsycInfo Database Record (c) 2025 APA, all rights reserved)