Objective: To compare the quality of semen in 1,055 Danish men born between 1950 and 1970 who are assumed to represent a random sample of the Danish male population of fertile age.
Design: Retrospective review of data on semen quality at the time of the female partner's first IVF treatment.
Setting: The Fertility Clinic, Odense University Hospital, Odense, Denmark.
Patient(s): One thousand fifty-five male partners of women with tubal infertility who were referred for IVF treatment consecutively during the period 1990-1996.
Intervention(s): Analysis of the semen samples delivered and used in connection with the couples' first IVF treatment.
Main outcome measure(s): Year of birth, age at time of sample collection, sperm concentration, and semen volume.
Result(s): The mean sperm concentration (+/- SD) was 183.7 x 10(6) mL and the mean semen volume (+/- SD) was 3.9 mL. A considerable variation in both parameters was found from year to year, but no significant change occurred in either parameter throughout the entire period. When four birth cohorts were compared, a later year of birth was not associated with any change in sperm concentration or semen volume.
Conclusion(s): Sperm concentration and semen volume were not related to year of birth, indicating that sperm quality has not changed in the Danish male population during the last 20-30 years.