Around 2000 men a year are diagnosed with testicular cancer in the UK. It is not known exactly what the causes are, but research is going on all the time to attempt to establish them.

Testicular cancer is more common in men who have a testicle that has failed to descend. In the unborn child the testicles develop inside the abdomen between the kidneys and descend into the scrotum at birth or during the first year of life. If this does not happen, the risk of a man developing testicular cancer is increased.

Men with a brother or father who has had testicular cancer are slightly more at risk of developing it (although the risk is still small). Research has shown that a particular gene is the cause of testicular cancer in some men. It is possible that this gene is inherited and may be the reason why testicular cancer sometimes occurs in brothers or sons of men who have had the disease.

Testicular cancer is more common in white men than African-Caribbean or Asian men. It occurs more commonly in wealthier social groups. The reasons for this are not known.

It is not clear whether injury to the testicle can cause a testicular cancer. Vasectomy does not increase the risk of a man developing testicular cancer.