Evidence for decreasing quality of semen during past 50 years

OBJECTIVE: To investigate whether semen quality has changed during the past 50 years. DESIGN: Review of publications on semen quality in men without a history of infertility selected by means of Cumulated Index Medicus and Current List (1930-1965) and MEDLINE Silver Platter database (1966-August 1991). SUBJECTS: 14,947 men included in a total of 61 papers published between 1938 and 1991. MAIN OUTCOME MEASURES: Mean sperm density and mean seminal volume. RESULTS: Linear regression of data weighted by number of men in each study showed a significant decrease in mean sperm count from 113 x 10(6)/ml in 1940 to 66 x 10(6)/ml in 1990 (p