Hypospadias: Pathophysiology and etiologic theories

Hypospadias is a congenital defect of the male urethra and phallus. Most boys with hypospadias have no other signs of under-masculinization or congenital malformations. The incidence appears to be increasing in the developed world. Evidence suggests that the etiology of hypospadias is multifactorial and that environmental conditions may have a role in the increasing incidence. The authors review normal male urethral development, epidemiology and the role of maternal-fetal hormone interactions, androgen synthesis, 5α-reductase, androgen receptor, environmental factors and assisted reproductive technology.