What is an undescended testicle?

While a baby boy is developing in the womb, the tissue that becomes the testicles (also called testes) begins to develop in the abdomen, just below the kidneys. Normally, as the baby develops, the testicles move down a canal (called the inguinal canal) into the scrotum. The scrotum is the sac that holds the testicles. When one or both of the testicles do not move down into the scrotum, the condition is called undescended testicle(s). It is also called cryptorchidism, which means "hidden testicle."

How often does it occur?

Undescended testicles occur in about 3% of full-term baby boys. It is more common in premature babies.

What is the cause?

The causes are complex and not the same for every boy. It can be caused by problems with different hormones or developing tissue. A specialist in urology can give you more information about the cause of your son's condition.

Occasionally, one or both testicles do not descend because the testicle is not there at all. This can happen if there was an interruption of the blood supply to the testicle(s) while the baby was developing and the testicle(s) never formed.

What is the treatment?

After the baby is born, most undescended testicles will continue their normal descent. More than 66% of the time, the testicle(s) will move into place naturally by the time your son is 6 months old. After 6 months, it is very unlikely that they will descend on their own.

If your child is older than 6 months, your health care provider will refer you to a urologist to review your treatment options. There are 2 types of treatment: surgery and hormone therapy. Surgery is recommended when the testicle has not descended very far. Hormone therapy may be recommended when the testicle has partially descended but is not yet out of the abdomen.

What are the complications?

Fifteen percent of boys who have one undescended testicle and 35% of boys with two undescended testicles will have fertility problems when they grow up. This is because an undescended testicle undergoes tissue changes when it does not descend normally. These tissue changes cause reduced sperm production. It is unknown whether treatment before 6 months of age helps to improve later fertility.

Boys who have had an undescended testicle also have an increased risk of hernias, urinary tract problems, and testicular cancer. Cancer is rare (only 1 in 2000 will develop testicular cancer).

If your child also has problems with his penis, your health care provider may send your child to a specialist in genetics.

When should I call my child's health care provider?

Call if:

• The testicle(s) has not descended by 6 months of age.
• You have other concerns or questions.