MACLEOD REVISITED - SPERM COUNT DISTRIBUTIONS IN 374 FERTILE MEN FROM1971 TO 1994

Objectives. There has been an enormous amount of interest as to whethe r sperm counts are declining over time, We sought to compare a contemp orary group of fertile men to those from the MacLeod study of 1951 to ascertain whether sperm counts in fertile men have changed over time. Methods. We obtained sperm count data from 374 fertile men who banked sperm in Minnesota prior to vasectomy from 1971 to 1994 and compared t hem to sperm count distributions from the 1000 fertile men of MacLeod' s study. Semen analyses were performed as per World Health Organizatio n guidelines using identical techniques in both the present and MacLeo d studies. Results, The contemporary group had a mean sperm count of 1 02 +/- 81 x 10(6)/mL (median 85 x 10(6)/mL) compared to 107 +/- 74 x 1 0(6)/mL (median 90 x 10(6)/mL) for MacLeod's data. There are no signif icant differences in mean or median sperm counts or sperm count distri butions between the groups. Conclusions. We find remarkable similariti es in sperm count distributions in cohorts of fertile men from 1951 an d 1971 to 1994. Sperm counts in fertile men have not changed appreciab ly in the 40 years since MacLeod's report. (C) 1998, Elsevier Science Inc. All rights reserved.