This chapter presents an overview of the current state of medical knowledge for treatment of children and adolescents with gender dysphoria. The chapter begins with an overview of the literature on how gender dysphoria is treated in childhood and adolescence, respectively. Medical treatment of relevance for pubertal youth is the primary focus. Next, the research on outcomes of medical treatment for trans youth is reviewed. The review is organised by reference to the staged treatment protocol: stage 1 – puberty blockers; stage 2 – gender affirming hormones; and stage 3 – surgery. Both physical and psychosocial effects of treatment are outlined. Lastly, to contrast, research is reviewed to determine what the likely outcomes are for trans youth if they do not receive medical treatment in adolescence. The review of medical knowledge surrounding the treatment of gender dysphoria reveals that there is substantial, and building, consensus around the appropriate treatment to be offered to trans youth in adolescence. It finds that while there may be a limited evidence base regarding long-term treatment outcomes, this is rapidly growing and supportive of treatment prior to adulthood.