Testis cancer causes?

Dumb luck: A few rare genetic syndromes put you at risk and there's a slight family tendency. A make-no-sense article a few years back blaming exercise probably reflected reporting bias. If you have a cryptorchid testis and it's not been fixed when it should have been, the risk is much higher. White guys are at the greatest risk, no one knows why.

Not clear: We know there is increase risk of having testis cancer in boys born with undescended testis and if a father or brother had testis cancer. In Many cases there is no known causes. There is new data showing that muscle building supplements may cause testis cancer.