Depressed semen quality: a study over two decades.

One hundred-eighty-five consecutive spermiograms from men of infertile couples in 1980-1981 were compared with as many spermiograms of age-matched controls from 1960-1961. The semen parameters analyzed were: volume, sperm density, and sperm morphology. The following significant changes were noted over the time period: the mean seminal volume decreased from 3.79 ml to 3.42 ml (p less than 0.05), the mean sperm count decreased from 125.4 mill/ml to 78.0 mill/ml (p less than 0.001) and the proportion of double sperm heads increased from 0.52% to 1.51% (p less than 0.001). Further analysis showed even more pronounced changes in these parameters for men living in the urban area compared those from the surrounding rural areas.