In hypospadias, one of the most common congenital anomalies in boys, the urethral meatus is located on the ventral aspect of the penis or even on the perineum. It is caused by incomplete closure of the tissue on the undersurface of the penis. The etiology of hypospadias is probably multifactorial, involving genetic and environmental factors. The treatment is surgery, the aim being a penis with normal appearance and function. The aim of this study was to assess the effects of hypospadias and its surgical correction on the life of the patient as an adult. It was also sought to establish the occurrence of this anomaly. In the clinical part of our series the study population comprised of 64 patients operated for hypopadias at Tampere University Hospital between 1963 and 1976. In a study comparing the sexuality of hypospadias patients to that of patients operated on the genitals, 64 patients circumcised for phimosis were selected as age-matched controls. The patient records of hypospadias patients were analyzed retrospectively and a questionnaire was mailed to them in 1994. All patients treated for hypospadias before nine years of age among boys born 1970-1986 were identified from the Finnish National Hospital Discharge Registry for a study of temporal trends and geographical variation in the prevalence of hypospadias in Finland. In a study of pregnancy-related risk factors of hypospadias, all 490 boys born with hypospadias in Finland between 1996 and 2001 were selected from the Finnish Birth Defects Registry and 1470 age-matched male controls from the Finnish Medical Birth Registry. Information on pregnancy-related factors was obtained from the Medical Birth Registry. Significant differences were noted between hypospadias and phimosis patients in erectile and urinary function, as well as in satisfaction with penile appearance and surgical result. Problems in voiding and erection and especially poor cosmetic result were associated with dissatisfaction with the outcome. Many patients would have preferred a longer follow-up after surgery. The mean prevalence of hypospadias among boys born 1970-1986 was much higher than had previously been reported, 28.1 per 10,000 male live births. It remained constant throughout the study period. Nonetheless, there was substantial geographical variation in the prevalence of operated hypospadias. Birth weight, young maternal age and presence of some anomaly other than hypospadias were risk factors for the condition. A great proportion of the previously reported differences between hypospadias patients and other men arise from surgery on the male genitalia and the out-of-the-ordinary appearance it causes. Even patients with a less than perfect technical result are able to live a satisfactory sexual life. An operation with good short-term results and few complications satisfies the patient also as an adult. The overall appearance as perceived by the patient is the most important factor in producing a good result. The previously reported low prevalence of hypospadias was due to underreporting of cases to the Finnish Malformation Registry. The geographical variation in the prevalence of operated hypospadias has many possible explanations, although none of them were verified by methods we used. Future studies on the relationship between poor intrauterine growth and hypospadias are clearly called for. A nutritional factor might provide a mode of intervention for the prevention of this disorder.