Transgender service in the US military: A scoping review

Abstract: Background: U.S. policies on transgender military service have changed five times over nine years, amid litigation and public debate, affecting service members diagnosed with Gender Dysphoria or who have received gender-affirming care. Opposition has centered on concerns regarding healthcare costs, unit cohesion, and service member character. This scoping review synthesizes the existing literature to characterize the evidence on transgender service in the U.S. military and inform policy discussions. Method: A systematic search of ten academic databases and six grey literature sources conducted between May and June 2025 identified 1713 records. Fifty-eight studies met the inclusion criteria and were analyzed following PRISMA-ScR guidelines, with attention to study characteristics and outcome domains. Results: Most studies were quantitative and conducted during periods of open transgender service. First authors were primarily affiliated with civilian universities in disciplines including political science, law, and policy. Common outcome domains included transition-related healthcare access and utilization, mental and physical health, and perceptions of transgender personnel by others. Transgender service members were estimated to comprise similar to 0.7% of the force, are predominantly younger, junior enlisted, and more often trans women. Findings indicate fewer transgender members than estimated, minimal impact on deployment readiness, and no evidence of harm to unit cohesion. Supportive leadership and affirming environments were consistently associated with improved mental health outcomes. Discussion: This scoping review found that evidence on transgender service is inconsistent with claims that these members compromise unit cohesion, impose disproportionate costs, or that access to gender-affirming care significantly affects readiness. These findings provide an empirically grounded basis for ongoing policy deliberations.