2011/12/06 by Gunter Heylens, Griet De Cuypere, Kenneth J. Zucker +5 · 1 citation
Biochemistry, Genetics and Molecular Biology · Psychology · Social Sciences · Medicine · #Sexual Differentiation and Disorders #LGBTQ Health, Identity, and Policy #Gender Roles and Identity Studies #Gender Identity Disorder #Etiology #Twin study #Psychology #Disorders of sex development #Concordance #Clinical psychology #Dizygotic twins #Developmental psychology #Gender identity #Medicine #Psychiatry #Internal medicine #Heritability #Biology #Genetics #Obstetrics #Social psychology
paper · doi:10.1111/j.1743-6109.2011.02567.x
openalex publication_date 2011/12/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/26
INTRODUCTION: The etiology of gender identity disorder (GID) remains largely unknown. In recent literature, increased attention has been attributed to possible biological factors in addition to psychological variables. AIM: To review the current literature on case studies of twins concordant or discordant for GID. METHODS: A systematic, comprehensive literature review. RESULTS: Of 23 monozygotic female and male twins, nine (39.1%) were concordant for GID; in contrast, none of the 21 same-sex dizygotic female and male twins were concordant for GID, a statistically significant difference (P=0.005). Of the seven opposite-sex twins, all were discordant for GID. CONCLUSIONS: These findings suggest a role for genetic factors in the development of GID.