Symptoms

Not seeing or feeling a testicle where you would expect it to be in the scrotum is the main sign of an undescended testicle.

Testicles form in the abdomen during fetal development. During the last couple of months of normal fetal development, the testicles gradually descend from the abdomen through a tube-like passageway in the groin (inguinal canal) into the scrotum. With an undescended testicle, that process stops or is delayed.

When to see a doctor

An undescended testicle is typically detected when your baby is examined shortly after birth. If your son has an undescended testicle, ask the doctor how often your son will need to be examined. If the testicle hasn't moved into the scrotum by the time your son is 4 months old, the problem probably won't correct itself.

Treating an undescended testicle when your son is still a baby might lower the risk of complications later in life, such as infertility and testicular cancer.

Older boys — from infants to pre-adolescent boys — who have normally descended testicles at birth might appear to be "missing" a testicle later. This condition might indicate:

• A retractile testicle, which moves back and forth between the scrotum and the groin and might be easily guided by hand into the scrotum during a physical exam. This is not abnormal and is due to a muscle reflex in the scrotum.
• An ascending testicle, or acquired undescended testicle, that has "returned" to the groin and can't be easily guided by hand into the scrotum.

If you notice any changes in your son's genitals or are concerned about his development, talk to your son's doctor.