Hypospadias means a malposition of the urethral opening on the underside of the penis. Rare cases of similar malformation in females have been described. The most severe forms have the urethral opening at the base of the penis or even on the perinaeum; the less severe have the urethral opening closer to, or on the underside of, the glans. The mildest forms do not need an operation.
Other genital anomalies are common (eg severely curved penis, undescended testis). The phase of penis development during which the maldevelopment occurs is driven by androgens, and hypospadias can be regarded as a mild form of incomplete masculinization of the male embryo.
Exogenous hormones, such as anti-androgens cause hypospadias. The defect results from incomplete masculinization of the male genitals, which can be mimicked with prenatal rats exposed to anti-androgens in laboratory conditions. Scientists in Europe have established that humans are currently exposed to sufficient levels of environmental pollutants, which under laboratory conditions can produce declines in sperm count and other reproductive problems in test animals. The role of oral contraceptives has also been considered.
This is a rather common malformation. Rates are extremely low in China, and exceptionally high in the USA, Canada, Israel and parts of central Europe. Differences are probably not totally explained by different criteria or detection. A recent medical study reports a doubling of hypospadias in male infants in the US between the 1970s and the 1980s, which together with similar reports from European countries and Japan, has raised serious medical concern.