Testicular cancer is rare, but it can affect teenagers and young men. The most common type in teenagers is teratomas.
It is not known why some people get testicular cancer, but there are a few factors that can increase your risk of developing the disease.
Some young boys need an operation if their testicles don't descend.
If your dad or brother has testicular cancer it increases your risk of developing it too.
It seems to be more common in white than black people
There is no link to injuries or sporting strains
It's best to check your balls regularly. A good time to do it is when you're in the bath or shower.
Testicular cancer usually only appears in one testicle. Look out for
If you have any of these symptoms it's important you get them checked out by your GP as soon as possible. Early treatment for testicular cancer is very successful.
Apart from an examination by your doctor, the main tests for testicular cancer are ultrasound and blood tests.
The treatment for testicular cancer is usually very good and most blokes are completely cured. The two main methods of treatment are surgery to have the cancer tumor removed and chemotherapy.