SAT394 Over-representation Of Adoptees Among Transgender Subjects Seeking Gender-Affirming-Hormonal-Therapy (GAHT) In A Large Tertiary Medical Center

Disclosure: I. Yaish: None. G. Keltch: None. Y. Greenman: None. T. Kolitz: None. K.M. Tordjman: None. Background: The etiology of transgenderism is still unclear. Possible mechanisms range from inborn brain-specific anatomical characteristics, to endocrine-related genetic polymorphisms. In addition, psychosocial developmental factors, particularly trauma from early childhood, are believed to contribute. In line with a handful of previous reports, we were struck by what seemed to be an over-representation of adoptees among adult subjects seeking GAHT at our Transgender Health Center. Aims of Study: To confirm that adopted individuals are more likely to seek a gender transition process than nonadopted subjects, and to determine whether there are major differences between the 2 subgroups. Design and Methods: A retrospective study of treatment-naïve adult subjects seeking GAHT at our center between 01.05.2014 and 31.12.2022. The prevalence of adopted subjects in the cohort was compared with the national rate by one sample binomial test. Adoptees were compared to nonadopted subjects in the cohort by nonparametric tests. Results: During the study period, 671 new adult transgender subjects initiated GAHT at our clinic. Among them, 14 adoptees or 2.09%, which is an order of magnitude greater than the corresponding national rate of 0.22% (P<0.0001). This rate is lower than that reported from clinics for transgender youth in Canada (7.6%), in the US (8.2%), and in Britain (3.8%). Age of adoption was at, or below, one year in 13 cases, and at age 2.7 yr in one. The distribution of assigned-at-birth sexes was different between the 2 groups. Among the 657 nonadopted subjects, the breakdown was quite balanced, 323 had been assigned male sex (49.2%), and 334 female (50.8%). Among adoptees, only 3/14 (21.4%) were born males, and 11 (78.6%) females, P=0.056, by Fisher’s exact test. There was also a trend for adopted subjects to be somewhat older than non-adopted subjects. Their median age was 25.5 yr [IQR 23-30.75], as opposed to 23 yr [IQR 19-30] in non-adopted subjects, P=0.08. Characterization, and comparisons of parameters such as socioeconomic status, co-morbidities, and others, are still ongoing. Conclusions: There is an over-representation of adopted adults requesting GAHT at our center. However, the rate is lower than what has been reported from pediatric clinics, suggesting some of these subjects may seek help at a younger age. The findings support a contributory role of adoption in early infancy and the trauma around it in the development of transgenderism. Further research should attempt to decipher the mechanisms through which this early life event interacts with inborn properties. Presentation: Saturday, June 17, 2023