Testicular Cancer is a disease in which malignant (cancer) cells form in the tissues of one or both testicles. Although the exact cause of most testicular cancers is unknown, there are a host of risk factors associated with testicular cancer that can increase the risk, but any male with testicles is susceptible to the disease.To see a list of the risk factors please visit our risk factors page.Source: http://www.cancer.org/cancer/testicularcancer/detailedguide/testicular-cancer-what-causes