Effect of increased scrotal temperature on sperm production in normal men

Objective: To determine whether application of polyester-lined athletic supports to bring the testes closer to the abdomen increases scrotal temperature and decreases sperm production. Design: Prospective clinical study. S etting: University academic medical center. Patient(s): Twenty-one healthy male volunteers. Intervention(s): The study consisted of a pretreatment period of 6 weeks, a treatment phase of 52 weeks, and a recovery phase until return to normal sperm production. During the treatment phase, the men wore polyester-lined athletic supports (single layer, double layer, or double layer impregnated with aluminum) throughout the day. Main Outcome Measure(s): Semen parameters and sperm function tests. Result(s): In all three groups of subjects, scrotal temperature was consistently increased by 0.8 to 1 degrees C while the subjects were wearing the athletic supports. Mean sperm concentration; sperm motility, morphology, and viability; sperm hyperactivation; and ability of spermatozoa to penetrate zone-free hamster oocytes were not affected by the increase in scrotal temperature. Conclusion(s): The increase in scrotal temperature induced by polyester-lined athletic supports was insufficient to cause significant suppression of spermatogenesis or alteration of sperm function. (C) 1997 by American Society for Reproductive Medicine.