Before the child is born the testicle migrates down from high in the abdomen and passes through abdominal wall and groin to take its normal position in the scrotum.
Undescended testicles are quite common.
Three-fourths of undescended testicles will descend within the first three months of life. The testicle may have not descended properly, but remains within the abdominal cavity. In some children the testes may be found in the groin, but can be brought down into the scrotum during examination. These 'retractile' testicles also will be seen to descend when the child is in the bathtub. Retractile testicles are due to hyperactive muscles that temporarily pull the testicle into the groin.