Transgender medicine is a relatively young field in which hormonal and surgical interventions are initiated primarily to address psychological and existential suffering associated with gender dysphoria. Since its emergence in the mid-twentieth century, gender-affirming care has remained scientifically, ethically, and politically contested. Recent debates have focused on puberty blockers for adolescents, with critics frequently pointing to the perceived lack of high-quality evidence.This paper examines what counts as scientific evidence in medicine and considers the evidence supporting gender-affirming treatment in adults. Because adult care has a longer clinical history and a more extensive empirical foundation than adolescent care, it provides a useful case for reflecting on the strengths and limitations of different forms of evidence. I argue that evidence-based medicine cannot be equated with randomized controlled trials alone. Real-world evidence, post-marketing surveillance, observational research, quasi-experimental studies, and clinical registries all contribute essential knowledge about effectiveness, safety, and long-term outcomes. The key questions are therefore not simply whether evidence exists, but evidence for what and evidence for whom. Addressing these questions is essential for advancing transgender healthcare while preserving both scientific rigor and ethical integrity.
Martin den Heijer (Mon,) studied this question.