Depressed semen quality in Swedish men from barren couples: a study over three decades

The semen quality of men who participated in an infertility investigation in 1956 was compared with that from men from similar populations in the years 1966, 1976, and 1986. The sperm parameters studied included total sperm count and sperm morphology. A significant reduction over this 30-year period was observed for both parameters. The total sperm count decreased from 467 million in 1956 to 305 million in 1986 (mean, p less than 0.0001) and the percentage of sperm with normal morphology diminished from 53% to 37% (mean, p less than 0.0001) during the same period. This Swedish study, like studies in other industrialized countries, indicates a decline in semen quality over the past few decades.