Objective: To determine whether there has been a decline in semen quality in a group of healthy men during the past 21 years.
Design: Retrospective analysis of the relationship between time and changes in semen parameters over 21 years using regression analysis.
Setting: A tertiary university center.
Patients: Five hundred ten healthy, normal men who donated multiple semen samples as participants in clinical studies between 1972 and 1993.
Main outcome measures: Sperm concentration, semen volume, total numbers of sperm per ejaculate, and percent spermatozoa with normal morphology.
Results: There was no decrease in sperm concentration, semen volume, total number of sperm per ejaculate, and percent normal sperm morphology in 510 healthy men studied between 1972 and 1993.
Conclusion: We conclude that in this population of healthy young men there has not been any decline in semen quality in the past 21 years.