SEMEN ANALYSES IN 1,283 MEN FROM THE UNITED-STATES OVER A 25-YEAR PERIOD - NO DECLINE IN QUALITY

Objective: To determine whether semen quality has changed in the Unite d States over the last 25 years. Design: Retrospective review. Setting : Three U.S. sperm banks, Cryogenic Laboratories, Inc. (Roseville, Min nesota), Idant Laboratories (New York, New York), and California Cryob ank, Inc. (Los Angeles, California). Patients: Twelve hundred eighty-t hree consecutive men who banked sperm before vasectomy from 1970 to 19 94. Intervention: None. Main Outcome Measures: Age at sample collectio n, sperm concentration, volume, motility, and days of abstinence befor e sample collection were determined for each man. Linear and multiple regression analyses were used to assess changes in these characteristi cs over time. Results: Controlling for the effects of age and duration of abstinence, there was a slight but significant increase in mean sp erm concentration but no change in either motility or semen volume ove r the 25-year period. Both sperm motility and semen volume decreased w ith increasing age at sample collection. Both sperm concentration and semen volume increased as a function of duration of abstinence. There were significant differences in mean (I-SEM) sperm concentrations (10( 6) sperm/mL) and motilities between the different sperm banks with Cal ifornia lowest (72.7 +/- 3.1, 51.4% +/- 1.1%, respectively), Minnesota higher (100.8 +/- 2.9, 56.0% +/- 0.5%, respectively), and New York hi ghest (131.5 +/- 3.5, 58.2% +/- 0.5%, respectively). Conclusions: Our data show no decline in sperm counts over a 25-year period in 1,283 me n who banked sperm before vasectomy at three distinct geographical sit es in the United States.