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DocSpot: Undescended testicles

Dear Dr Margaret
My problem is that my boyfriend has one testicle and can feel the second one inside. Is there any advice you could put on your site for this problem? He’s very scared about going to a doctor.

Dear Dr Margaret
Please help me. I have just turned 18 and I still have only one testicle. I am getting pains in my lower abdomen. Could this be cancer? I am too embarrassed to go to the doctor to find out why I have only one testicle.

Your testicles started to develop when you were a tiny fetus (a few weeks after you were conceived). They began high inside your abdomen, near the kidneys at the back. About 6 months before you were born, they started to move forwards and downwards towards the groin. Meanwhile, your scrotum was developing ready to receive them. About 1-2 months before birth, the testicles normally complete their journey by descending into the scrotum.

In about 3–4% of boys, one testicle doesn’t make the journey from the back of the abdomen to the scrotum. Instead, it becomes stuck inside the abdomen or at the groin. This is called an ‘undescended testicle’. No-one knows why it happens, but it does seem to be getting more common. The scrotum will be empty on one side. If the testicle is at the groin, it may be possible to feel it there. Most babies with an undescended testicle do not need any treatment – in three out of four cases, the testicle will come down naturally before the baby is 3 months old. If not, the baby often has an operation at about 18 months of age. If you want to know more, look at an excellent article by top American expert, Professor Steven Docimo, Director of Pediatric Urology at The Children’s Hospital of Pittsburgh, USA, at You can also find information at

If you are a teenager or an adult with an undescended testicle, you should definitely see your doctor. Your doctor should refer you to a hospital specialist (urologist). There is no need to feel at all embarrassed, because all doctors know this is a problem that needs attention. There are at least three issues that you will need to discuss with the urologist.

Firstly, an undescended testicle is slightly more likely to develop cancer than a normal testicle. The risk is roughly 1 in 2,000 (the risk of testicular cancer in all men is about one in 100,000). Cancer of the testicle is almost always curable, partly because men easily notice a lump on their testicle and therefore it is caught at an early stage (see How to examine your testicles and Lumps on the genitals - the scrotum). But if the cancer develops in a testicle that is hidden up in the abdomen, it will be difficult to detect. A testicle that has become stuck in the abdomen is unlikely to be producing sperm, so the urologist may suggest that you have an operation to remove it, to prevent it becoming cancerous in the future. This is a complicated decision, which you will have to discuss in detail with the urologist. It may depend partly on your age; cancer of the testicle is most common in young men, so after the age of about 32 years, the risk of the operation may outweigh the likelihood of getting cancer and it might be better to do nothing.

Secondly, if you have an undescended testicle, you may be worrying about fertility. Although the undescended testicle probably isn’t doing much, you need not be too worried because your other normal testicle is likely to be producing many millions of sperms.

Thirdly, an undescended testicle is not firmly anchored, and can become twisted on the tissues that surround it. This is called ‘torsion’. Episodes of torsion are very painful. So if you have abdominal pain as well as an undescended testicle stuck in the abdomen, your doctor will need to consider the possibility of torsion.

Fourthly, if having an empty scrotum on one side bothers you, you can ask the urologist about having an artificial implant to give the appearance and feel of a normal testicle. These are either silicone or a silicone bag filled with saline (similar to a breast implant). However, Professor Docimo says that many men are content with just one testicle, and don’t want an implant.


Dear Dr Margaret
My husband and I have been trying for a baby. When he was a child he had an operation to bring his testicle down. Could this have affected his fertility?

Your question is not easy to answer, but the key point is that his fertility (ability to father a child) may relate to how old he was when he had the operation for undescended testis (testicle).
Most of the research has been done on sperm counts. If the sperm count is low, conceiving a baby could be problematic. Studies of men who had an operation for undescended testis more than 25 years ago suggest that the sperm count could be affected.
  • If both testes had to be brought down, only about one in four men have a normal sperm count. About half will have no sperm, or very few.
  • If only one testis had to be brought down, about half have a normal sperm count.

We now know that the later the operation, the worse the result for fertility, but no one knew that in the 1970s. Therefore, the reason for such a large effect in these research studies is probably that they go back 25 years, when the operation to bring the testis down tended to be done in late childhood.

If the operation was done before he was 4 years old, the sperm count will be much better. In fact, the sperm count is likely to be normal. This is backed up by studies of samples taken from the actual testis at the time of operation, which show no defect if the operation was done before the age of 1 year. Because of this research, surgeons are now doing operations for undescended testis much earlier than previously.
If you want more general information about undescended testis, look at the section on testicle problems.
I should point out that the volume and appearance of your husband’s semen each time he ejaculates does not tell you anything about the number of sperm it contains. This is because most of the volume of the semen comes from other glands, such as the prostate and ‘seminal vesicles’. Only about 5% comes from the testes. The only way for him to find out his sperm count is to have his semen analyzed at a fertility clinic. If his sperm count is low, various special techniques can help fertilization. For example, a sperm can be injected directly into one of your eggs. And to put the problem in perspective, about 15 –20% of all couples have difficulty conceiving a baby, so any problems you have may not be connected to his previous testis problem.

Sources of information

McAleer IM, Packer MG, Kaplan GW et al. Fertility index analysis in cryptorchidism. Journal of Urology 1995;153:1255–8.
Leung AK, Robson WL. Current status of cryptorchidism. Advances in Pediatrics 2004;51:351–77.
O’Brien M, Chandran H. Maldescent of the testis. Surgery 2004;22:252–5.

Last updated; Friday, November 9th 2012 at 1:10 am

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