Undescended testicles 

Undescended testicles are a common childhood condition where a boy is born without having one or both testicles in their scrotum. The medical term for undescended testicles is cryptorchidism.

The scrotum and testicles

The scrotum is a small sac of skin that hangs underneath the penis. It holds the testicles in place.

The testicles are the two oval-shaped male sex organs that sit inside the scrotum on either side of the penis. Testicles are an important part of the male reproductive system as they produce sperm and the hormone testosterone, which plays an important role in male sexual development.

The development of the testicles

During pregnancy, the testicles form inside the baby’s abdomen (the area of the body that contains the stomach), before slowly moving down into the scrotum as the baby develops. The testicles are usually in place by the eighth month of pregnancy.

For reasons that are still unclear, one or both testicles sometimes do not move into the scrotum by the time the baby is born.

The need for treatment

Having undescended testicles does not present any immediate health problems, and it is painless. In many cases, the testicle(s) will descend into the scrotum some time during the first four months of the baby’s life.

If the testicle(s) do not descend by this time, treatment is usually recommended.

Treatment is usually recommended for three reasons. Boys with undescended testicles:

• may have fertility problems in later life
• have an increased risk of developing testicular cancer
• may have problems with their self-esteem and body image if they are ‘missing’ one or both of their testicles.

Treatment options include:

• using artificial hormones to stimulate the descent of the testicle(s)
• using a type of surgery, known as an orchidopexy, to move the testicle(s) into the correct position inside the scrotum. This is more common

How common are undescended testicles?

Undescended testicles are one of the most common congenital conditions that affect boys. Congenital means that the condition is present at birth. It is estimated that 3-5% of newborn boys have undescended testicle(s).

In around 80% of cases, only one of the testicles is affected. Most cases will resolve without the need for treatment, although a small number of boys (0.7-1%) have testicles that stay undescended into adulthood unless treated.

Outlook

The outlook for boys who are born with persistent undescended testicles is usually very good. In most cases, orchidopexy is a relatively straightforward type of surgery that has a good success rate. If the condition is treated at an early age, the boy’s fertility should be unaffected.

Boys who are born with undescended testicles have an increased risk of developing testicular cancer later in life, although this risk is very small (an estimated one in 1,000-2,500 chance).