Worldwide variations in sperm counts.

OBJECTIVES

Based on the premise that various human disease processes manifest differently depending on geography, we set out to determine whether sperm counts vary from different nations and different regions within the United States.

METHODS

We reviewed the literature of all significant population-based studies that evaluated sperm counts from fertile or presumably fertile men from 1930 to the present.

RESULTS

We found that sperm counts did, in fact, vary greatly. Throughout the United States, average sperm counts ranged from a low of 48 million/cc in lowa to a high of 134 million/cc in New York, with multiple values in-between from Texas, Minnesota, Washington State, and California. Internationally, average sperm counts ranged from a low of 52.9 million/cc in Thailand to a high of 102.9 million/cc in France.

CONCLUSIONS

We conclude that sperm counts are subject to a wide range of variation among geographic locations.