The compatibility between genetic, gonadal, genital, somatic and psychic sex should be present for the proper sexual development. If there is no such compatibility, disorders of sex development (DSD) appear. Medical procedure in such cases leads to many problems which mainly come from the lack of sufficient knowledge about the pathophysiology of the disorders. The main difficulties met by diagnostic and therapeutic team are: determination of the official sex, prediction of gender identity, hormonal activity of gonads and fertility, as well as the decision to undertake surgical procedures involving the genitals and gonads. Disorders of sex development lead also to psychological problems of patients and their families, because they disturb the proper social functioning.