Dramatic increase of gender dysphoria in youth In the past decade there has been a dramatic increase in the number of young people with gender dysphoria seeking help for gender-confirming medical interventions. From a situation of no more than a few patients annually, there were almost 200 referrals of gender dysphoria to the Astrid Lindgren Children's Hospital in 2016. This child and adolescent psychiatric unit has the whole country as a catchment area for patients <16 years. Gender-confirming medical interventions are regulated by a special law that sets a minimum age for legal and surgical gender reassignment to 18 years. The law, which is under revision, does not prevent medical investigations, hormonal therapy, and some surgical procedures before the age of 18. Gender dysphoria is defined as a persistent desire to live and be accepted as the opposite sex, usually accompanied by a perceived inconsistency with the sex assigned at birth and a desire to change the body in accordance with the perceived sex. The cause is unknown despite attempts of etiological mapping including genetic analyses, hormonal studies and modern brain imaging techniques. Repeated studies have shown that only a minority (about 20 %) of prepubertal children with gender dysphoria will have a persistent desire for later gender-confirming medical interventions, while the majority of those whose gender dysphoria is reinforced during puberty will later meet the diagnostic criteria for gender dysphoria (DSM-5) and transsexualism (ICD-10) (so called persisters). Persisters can be offered treatment with puberty stopping hormones to avoid the development of undesirable secondary sexual characteristics. Gender-confirming medical interventions are the only recommended treatment for gender dysphoria, and early treatment facilitates the ability to successfully pass in the desired sex, which is associated with a significantly better prognosis.