New data confirming a circannual rhythm in spermatogenesis.

Our study demonstrates a circannual rhythm in spermatogenesis by 2697 spermiograms of healthy probands and subfertile patients. This rhythmicity is valid both for fertile as well as for subfertile men. In both groups, the lowest values of sperm count occurred in the summer while the peak values occurred in the winter and spring. For basal diagnostic purposes in male hypofertility, spermiograms should be obtained before or after the summer months. In oligospermia seasonal fluctuation in sperm density should be taken into account in in vitro fertilization and in artificial insemination, homologous.