Genetic and Environmental Contributions To Gender Diversity: A Systematic Review of the Twin Literature

Abstract

Amidst growing visibility of gender diversity, the aetiology of gender identity has become a subject of increasing public interest. Prompted by the growing public debate, we review here the extant twin literature regarding the origins of gender diversity. Literature was reviewed systematically, searching Medline, Embase and PubMed databases. Studies were deemed eligible if they: (i) conducted a twin study, (ii) investigated gender identity or gendered behaviour, and (iii) provided an estimate of the magnitude of genetic or environmental contribution. After screening 290 non-duplicate titles and abstracts, 16 articles were included in the final review. Most eligible studies provided evidence ..