The short answer is any male with testicle(s). Testicular cancer is the most common cancer in males ages 15-34, although many cases fall outside these parameters. There is one male diagnosed every hour with testicular cancer.

Risk Factors:

Below are some of the risk factors associated with the disease.

• Having an undescended testicle. This is a condition in which one or both testicles fail to move from the abdomen, where they develop before birth, into the scrotum. Undescended testicles may increase the risk for development of testicular cancer. Also called cryptorchidism.

• Having had abnormal development of the testicles

• Having a personal history of testicular cancer. About 3-4% of men who have been cured of cancer in one testicle will eventually develop cancer in the other testicle.

• Having a family history of testicular cancer (especially in a father or brother). Don’t worry, only a small number of testicular cancers occur in families. Most men with testicular cancer do not have a family history of the disease.

• The risk for testicular cancer is about 4-5 times great in white males compared to black men and that of Asian –American men. The reason is unknown, but the risk of developing the disease is also highest among men living in the United States and Europe.

• Testicular cancer is the most common cancer in males ages 15-34 

Risk Factor Myths (unproven/controversial risk factors):

There are numerous myths and controversial activities that people believe contribute to the disease, including horseback riding, a prior injury or trauma to the testicles, cycling, and strenuous activity.

Source: http://cancer.gov