Hypospadias: a familial study.

The families of 177 boys with varying degrees of hypospadias were evaluated prospectively to determine the occurrence of hypospadias and other congenital anomalies within this population. A significant number of male subjects in each family member category were affected, with first degree relatives (brothers and fathers) having a 14 and 9 per cent incidence, respectively. Siblings were at a greater risk for having this anomaly when the proband had a more severe degree of hypospadias and when the abnormality also was present in other relatives. A multifactorial mode of inheritance is suggested as the basis for transmission of this congenital defect.