We evaluated the incidence of hypospadias and its effects on psychosexual development in a sample of 11,649 young Italian males. Over the last 30 years only about 30 major publications have addressed these issues and the results of many studies have been contrasting. Some defects in methodology, such as low response rates, heterogeneity of age ranges and the choice of controls, have been the main limitations. Our study was designed to take these problems into account. Forty-two hypospadic subjects and a random sample of 500 nonaffected males selected from the large sample of 11,649 young men (>90% of the 18-year-old males living in the Italian region of Tuscany) were screened by the Minnesota Multiphasic Personality Inventory (MMPI) test, psychological interview and clinical evaluation. The incidence of hypospadias in this representative group of Italian men is 3.6/1,000. No difference was noted in the percentage with altered MMPI compared with the control group. The age at surgical corrections and the number of operations are not related to an abnormal global psychological adjustment. Severity of disease influences a more negative genital appraisal and the number of operations is correlated only with more difficulty in initiating contact with the opposite sex. Surgery for hypospadias has to be strongly pursued in as many cases as possible. In addition, we strongly recommend following up all hypospadics, independently of the severity of their genital malformations, through adolescence to early adulthood, to ensure early detection of subjects with impaired psychological profiles. Copyright 2002 S. Karger AG, Basel