Relation between morphologically abnormal spermatozoa and pregnancies obtained during a twenty‐year follow‐up period

The clinical fertility of 1077 men investigated with semen analysis including detection of morphologically abnormal spermatozoa during the years 1950-52 was studied 20 years later using a questionnaire replied to by 785 (72.9%). There was a significant correlation (P less than 0.01) between increasing number of abnormal spermatozoa and decreasing chance of getting living children, but no relation to abortions and pathological pregnancies. Moreover, there was a significant correlation (P less than 0.01) to time-interval to first pregnancy. Median values for those obtaining living children was 25% abnormal spermatozoa compared with 28% for those not doing so. Up to 60% abnormal spermatozoa, fertility was not reduced, and the borderline between normal and reduced male fertility is therefore defined to be 60% morphologically abnormal spermatozoa.