Biological and psychosocial evidence in the Cass Review: a critical commentary

BackgroundIn 2020, the UK's National Health Services (NHS) commissioned an independent review to provide recommendations for the appropriate treatment for trans children and young people in its children's gender services. This review, named the Cass Review, was published in 2024 and aimed to provide such recommendations based on, among other sources, the current available literature and an independent research program.AimThis commentary seeks to investigate the robustness of the biological and psychosocial evidence the Review-and the independent research programme through it-provides for its recommendations.ResultsSeveral issues with the scientific substantiation are highlighted, calling into question the robustness of the evidence the Review bases its claims on.DiscussionAs a result, this also calls into question whether the Review is able to provide the evidence to substantiate its recommendations to deviate from the international standard of care for trans children and young people.