[The wrong sex].

Sexual ambiguity may cause problems in determining the sex, in which a child would be reared. Three case histories of such patients are presented, in which the initial diagnosis proved to be incorrect. Arguments which lead to the ultimate choice of the sex of the child ranged from strict medical, to psychosocial and even cultural considerations. A simple classification of causes of ambiguous external genitalia is used both for investigation and management of these patients. Only expert examination shortly after birth allows an early and definite decision, avoiding more serious problems in later life.