Male Fertility Trends in the 21st Century
Anthony J. Thomas, Jr., M.D. and Ashok Agarwal, Ph.D.

Whether fertility in men is decreasing worldwide is the subject of great controversy. Despite great concern, especially about a possible decline in sperm counts, few researchers have documented the incidence of sperm abnormalities.

To help judge whether these concerns are founded, we reviewed data from more than 1,000 men who came with their wives to the Cleveland Clinic for fertility evaluation in the year 2000. In looking at the records of nearly 700 men who had complete semen analysis, we found the incidence of oligospermia alone to be very low - only 5%. Low sperm count is not the major cause of poor sperm quality. Morphology and motility defects are more common. If fertility is impared, our data show, it is more likely the result of dysgenesis than spermatogenesis.

About a quarter (24%) of the men had no sperm abnormalities. The remainder (75%) had some abnormality - either low counts, abnormal morphology, or low motility or any combination of these. The incidence of abnormal morphology or teratospermia among men seeking evaluation for fertility is high (84%). Many men who have normal counts and motility (43%) have teratospermia. These results emphasize the importance of accurately assessing sperm morphology in a routine infertility work-up, not just counts and motility.

Not only were we able to document the incidence of these abnormalities, but also the incidence of leukocytospermia, an indicator of infection and a possible factor in infertility. We found leukocytospermia (>1x106 WBC/mL) in about 15 to 20% men with normal and abnormal semen alike, with no significant difference between them. The incidence of leukocytospermia in patients coming for an infertility evaluation is nonspecific and indicates a lack of correlation with any of the semen abnormalities, either as a cause or effect. The group that showed significantly more leukocytospermia than others was the group of men with a combination of all three semen abnormalities - ologoasthenoteratospermia or OAT syndrome.

Table 1
Incidence of Various Semen Abnormalities in All Men Evaluated for Infertility

Table 1

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Last Update : December 29, 2008
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