A risk factor  is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.
The following factors can raise a man’s risk of developing testicular cancer. However, it is important to note that the cause of testicular cancer is not known.
Age. Testicular cancer is most common in men between the ages of 20 to 45. However, men of any age can develop this disease, and it’s important that any man with symptoms of testicular cancer  visit the doctor.
Cryptorchidism (undescended testicle). Men with this condition, in which one or both testicles do not descend into the scrotum before birth as they normally should, have an increased risk of developing testicular cancer. This risk may be lowered if surgery is performed to correct the condition before the boy reaches puberty. Some doctors have recommended that cryptorchidism be corrected when a boy is very young, between six and 15 months, in order to reduce the risk of infertility (inability to produce children). Because cryptorchidism is often corrected at a young age, many men may not know if they had the condition.
Family history. A man who has a close relative (particularly a brother) who has had testicular cancer has an increased risk of developing testicular cancer.
Personal history. Men who have had cancer in one testicle have an increased risk of developing cancer in the other testicle. It is estimated that out of every 100 men with testicular cancer, two will develop cancer in the other testicle.
Race. Although men of any race can have testicular cancer, white men are more likely than men of other races to be diagnosed with testicular cancer. Testicular cancer is rare in black men, but black men with testicular cancer are more likely to die of the cancer than white men, particularly if the cancer has spread beyond the testicle to the lymph nodes or other parts of the body when it is diagnosed.
Human immunodeficiency virus (HIV) infection. Men with HIV or AIDS (acquired immune deficiency syndrome caused by the HIV virus) have a slightly higher risk of developing seminoma.