Undescended testes in children: the paediatric urologist's point of view.

Undescended testes (UDT) are found in 1% boys at the age of 1-year old, 3% of full-term male infants and 33% in premature babies at birth. Spontaneous descent is possible until 6 months of age. The two main phases of descent of the testis during gestation are described, as well as the possible aetiologies, the consequences of an abnormal migration, and the main locations of UDTs. Clinical examination is essential and should be done in optimal conditions. Laparoscopic exploration is the only valuable complementary investigation in the case of non-palpable UDT.