Undescended testicles are a condition that occurs when one or both testicles fail to move into the scrotum before birth. The condition occurs in about 3 – 4% of full-term infants and is fairly common in premature infants. In most cases the testicles descend by the time the child is nine months old. Testicles that do not descend by the time the child is one year old should be carefully evaluated. Treatment, including hormone injections (such as human growth hormone or testosterone) or surgery, may be needed.
Testicles that do not naturally descend into the scrotum are considered abnormal. These undescended testicles have an increased likelihood of developing cancer later in life, regardless of whether or not they are surgically brought down into the scrotum. When an undescended testicle occurs on one side, even the normal one has a slightly increased risk of developing cancer. In addition, undescended testicles can contribute to infertility later in life. All men should perform monthly testicular self-exams, but men who have an undescended testicle need to be particularly cautious.