The exact causes of testicular cancer are unknown.

Several conditions may increase your risk of getting testicular cancer. (Most men who get testicular cancer don't have any risk factors.) These risk factors include:^{1, 3}

• An undescended testicle (cryptorchidism). This is a testicle that has not descended from the abdomen into the scrotum. Normally, the testes descend into the scrotum before the male fetus is born or during the first 3 months of infancy.
• Klinefelter syndrome. This is a genetic disorder that affects males. Normally, males have one X and one Y chromosome. Males with Klinefelter syndrome have at least two X chromosomes and, in rare cases, as many as three or four.
• A family history of testicular cancer.

Infertility from sperm problems has been linked to testicular cancer. Men with sperm problems have a higher rate of testicular cancer than men who do not. Experts don't yet know if the two problems share the same cause, or if one causes the other.⁴

Some doctors recommend that men between the ages of 15 and 40 perform a monthly testicular self-examination (TSE). Others do not believe a monthly TSE is necessary for men who are at average risk of developing testicular cancer. Monthly TSEs may be recommended for men at high risk of developing testicular cancer, including those who have one or more of the above risk factors. If you have increased risk, you should see your health professional regularly for testicular examinations because painless changes in the testes may go unnoticed during a self-examination.