[Testicular germ cell tumors--epidemiology and risk factors].

An increasing incidence of testicular germ cell tumours has been observed in many white populations in this century. Ethnic genetic implications and lifestyle seem to influence the development of testicular cancers, whereas the influence of intrauterine conditions is under debate. Epidemiologic studies cannot explain the increasing incidence among young men. The age variation of incidence and histologic type indicates at least two different aetiological mechanisms. Testicular cancers among young men are most probably due to gonadal dysgenesis, whereas in old men they reflect the general increased risk of cancer with old age. The increased risk of developing testicular germ cell tumours among cryptorchid young men supports the gonadal dysgenesy hypothesis.