Circannual rhythms of sperm parameters of fertile men

Mean monthly values for ejaculate volume, sperm density, and percentage of motile sperm were calculated from semen analyses performed on volunteered donors to the laboratory from 1979 to 1986. The data of 4,196 ejaculates were computerized by the single Cosinor method for searching on circannual rhythms of the parameters. The study does not detect circannual rhythms, neither of the ejaculate volume nor of the percentage of motile sperm. A statistically significant high-amplitude seasonal variation was detected in sperm court, the highest values being recorded in late winter and early spring, the lowest values being recorded in late summer.