Longitudinal study of semen quality in Wisconsin men over one decade.

To determine whether there has been a time-related change in semen quality, we examined a Wisconsin population of men over a 10-year period. The semen quality of potential sperm donors was assessed between the years 1978 and 1987. The semen analyses included sperm concentration, motility, and morphology. No significant changes over time were observed for sperm concentration or motility. The percentage of morphologically abnormal sperm rose sharply between 1982 and 1983. This, however, coincided with a change in criteria used to identify abnormal sperm, and was, therefore, due to a procedural artifact. In summary, we found no evidence of a decline in semen quality in our Wisconsin population over a 10-year period.