Testis cancer with germ cells is the most frequent cancer of young men and its incidence is in constant increase in many industrialized countries, as in France. An increased risk of developing testis cancer has been described in patients with testicular ectopia history and testicular cancer history (controlateral testicular cancer) and more recently suggested in a population of hypofertile men with altered spermatogenesis. To a better understanding of this risk, an attempt of characterization of this group of patients has been proposed in the present work.