Sexual maturation disorder is a disorder of anxiety or depression related to an uncertainty about one's gender identity or sexual orientation. The World Health Organization (WHO) lists sexual maturation disorder in the ICD-10, under "Psychological and behavioural disorders associated with sexual development and orientation". In the ICD-10 it is explicitly stated that sexual orientation, by itself, is not a disorder and is not classified under this heading. Sexual maturation disorder, along with ego-dystonic sexual orientation and sexual relationship disorder, was introduced to the ICD in 1990, replacing the ICD-9 diagnosis of homosexuality. The diagnosis is not included in the ICD-11.