Transsexuality and adolescence Being transsexual (the feeling of mentally belonging to the opposite sex from one’s biological sex) is established at birth and is caused by various little-known factors that begin to act as early as the fetal stage. However, other circumstances (family relationships) in childhood and adolescence (puberty) might also influence this phenomenon. The discrepancy between mental and biological sex produces discomfort and distress, which may occur to varying degrees, from mild to extreme. Transsexuals seek to modify their sexual characteristics using hormonal and surgical treatment. For transsexuals who have come of age, the therapeutic approach is well established and consolidated. However, the approach in adolescents is controversial. Most (80-95%) prepuberal children reporting they feel transsexual will feel otherwise in adolescence. Moreover, several findings have suggested that, in addition to secondary sexual characteristics, cognitive and behavioral functions are also formed in adolescence. Altering the appearance and physiological development of the events of this stage by bringing forward hormonal and surgical treatment in transsexuals could adversely affect these functions. Parental attitudes, which could be a key influence in determining adolescents’ feelings and precipitating treatment, should be considered. The diagnostic approach takes longer in adolescents than in adults, and the therapeutic decision should be individualized. There is firm consensus that surgical sex reassignment should not be carried out until individuals have come of age.