Scrotal temperature is low than the abdomen about 3-4 ℃ in most of the mammals.Scrotal hypothermia is essential for normal spermatogenesis.Sertoli cell (Sc) is important in determining fate of spermatogenic cells by providing nutrition and structural support via cell junctions.We have demonstrated that experimental cryptorchildism or local worming testes at 43℃ for 2 consecutive days (30 min per day) in rhesus monkeys induced reversible oligospermia/azoospermia by germ cell apoptosis, and reversible functional changes in somatic cells of seminiferous epithelium by Sc dedifferentiation and Leydig cell hyperplasia.