Variation in sperm penetration assay related to viral illness

Semen specimens from a single pregnancy-proven fertile donor were evaluated in the SPA on a weekly basis over a 4-month period that included a febrile viral illness. This report documents the time course for recovery of decreased sperm density and decreased egg-penetrating ability of human sperm after a febrile viral illness. Observations from these data suggest that egg penetration ability monitored in the SPA is acquired in the testicle during early to midspermiogenesis. This finding contrasts with the more commonly held belief that fertilization capabilities are acquired during epididymal transit.