Undescended testicles

My baby boy has an undescended testicle. What does this mean?

Some baby boys are born with just one testicle in the skin sac, or scrotum, that lies behind their penis. Usually, the missing testicle is present, but it is higher up than it should be, in your baby's tummy. In some children, this happens to both testicles. Whether one or both testicles are undescended, the medical term is cryptorchidism.

This condition is common. It is more common in babies who are born prematurely (Sumfest 2009).

Checking for an undescended testicle should be part of your newborn baby's routine checks. Your doctor will have a look and feel to find out whether both your baby's testicles are in his scrotum (Tekgül 2008).

It's likely your baby's testicles will come down on their own (Virtanen 2008). For this reason, doctors usually wait to start treatment. However, if your baby's testicles have not descended by six months, your doctor is likely to recommend surgery.

What causes an undescended testicle?

In most baby boys, the testicles move down into the scrotum after 28 weeks of pregnancy (Sumfest 2009, Virtanen 2008). An undescended testicle becomes stuck either in the tummy or groin.

This is one reason why undescended testicles are more common in premature babies. These babies are simply born before the testicles have had time to make their usual journey.

Generally, though, no one knows for sure what the cause is. It could be that smoking or drinking alcohol during pregnancy has an effect on the testicles, but this is only a theory.

It's also possible that exposure to something in the environment, such as chemicals, is the cause. Again, the evidence is not complete. Part of the reason may be genetic, that is, babies inherit it from their parents (Barthold 2008, Main 2009).

Sometimes undescended testicles occur along with other medical problems, such as a small opening in the tummy muscle wall, called a hernia (Virtanen 2008).

What problems can it cause?

There are four main concerns with undescended testicles:
  • Your son's fertility may be affected when he grows up. Sperm need to be kept cooler than body temperature.
  • There is a chance that the testicle could be damaged or injured if it is left above the scrotum.
  • He has a higher risk of testicular cancer in the future.
  • He might be upset because of the way it looks.

What is the treatment for an undescended testicle?

The main treatment is surgery. If the testicle has not descended by the time your child is six months, your doctor will probably recommend an operation called an orchiopexy. Your child will be asleep for the operation, under an anesthetic. The surgeon will look for the testicle, see if it is healthy, and bring it down into its place in the scrotum. Some children need to have the surgery in stages, with two operations (Bannon 2007, Thorup 2007).

There is some risk that the testicle may be damaged during the operation (Sumfest 2009). Also, in some children the testicle goes back up again after surgery, so your son should have check-ups from time to time.

Surgery does not eliminate the risk of testicular cancer when your son is older (Bannon 2007). But it can reduce the risk if he has the operation when he's young (Walsh 2007). Having the testicles down in the scrotum does make any lumps easier to detect. When he reaches puberty, your son should be encouraged to examine his testicles for lumps. Your doctor can teach him how to do this.


Abdullah NA, Pearce MS, Parket L et al. 2007. Birth prevalence of cryptorchidism and hypospadias in northern England, 1993-2000. Arch Dis Child 92:

Bannon M, Carter Y. 2007. Practical paediatric problems in primary care. Oxford University Press. ISBN: 978-0-19-852922-4

Barthold JS. 2008. Undescended testis: current theories of etiology. Curr Opin Urol 18: 395-400.

Main KM, Skakkebaek NE, Toppari J. 2009. Cryptorchidism as part of the testicular dysgenesis syndrome: the environmental connection. Endocr Dev 14: 167-73.

National Screening Committee. 2006. Policy: Cryptorchidism screening.

Sumfest JM, Kolon TF, Rukstalis DB. 2009. Cyptorchidism.

Tekgul S, Riedmiller H, Gerharz E et al. 2008. Guidelines on paediatric urology. European Association of Urology.

Thorup J, Haugen S, Kollin C et al. 2007. Surgical treatment of undescended testes. Acta Paediatr 96: 631-7

Virtanen HE, Toppari J. 2008. Epidemiology and pathogenesis of cryptorchidism. Hum Reprod Update 14: 49-58.

Walsh TJ, Dall'era MA, Croughan MS et al. 2007. Prepubertal orchiopexy for cryptorchidism may be associated with lower risk of testicular cancer. J Urol 178: 1440-6. Abstract:

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