People who have gender dysphoria feel strongly that their gender does not match their biology. Gender identity disorder is a condition characterized by a persistent feeling of discomfort or inappropriateness concerning one's anatomic sex. The disorder typically begins in childhood with gender identity problems and is manifested in adolescence or adulthood by a person dressing in clothing appropriate for the desired gender, as opposed to one's birth gender. In extreme cases, persons with gender identity disorder may seek gender reassignment surgery, also known as a sex-change operation.