[Obvious aspects of the external genitalia in disorders of sexual differentiation].

Birth of a child with intersexual external genitalia poses a severe psychological burden for the parents. Therefore, it is of utmost importance to find the correct diagnosis quickly. Inspection of the genitalia might already give important hints. Serological and molecular genetic examinations can verify the diagnosis in the majority of cases. Chromosomal analysis is obligatory.To understand the different appearances of intersexual genitalia, first the normal embryological sexual differentiation is explained in the article. Then the aspects of virilized genitalia in cases of a chromosomal 46,XX child and of female appearing genitalia in cases of a chromosomal 46,XY child are described. Differences are analysed. Besides mentioning the main causes of disorders in sexual differentiation a brief summary of diagnostics and therapeutic considerations is given.