WHAT IS MALE INFERTILITY?

Infertility is the failure of a couple to become pregnant after one year of regular, unprotected intercourse. In both men and women the fertility process is complex, and, in many cases, infertility is caused by a combination of problems in both partners that conspire to prevent conception.

About 10% to 15% of couples experience some form of infertility, and, in approximately 40% of these cases, male infertility is the major factor. Another 40% of infertility problems are caused by abnormalities of the woman's reproductive system, and the remaining 20% involve couples who both suffer reproductive difficulties.

Infertility affects one in 25 American men. More than 90% of male infertility cases are due to low sperm counts, poor sperm quality, or both. Whether sperm counts are declining overall in industrialized countries is a controversial issue

 Declining Male Fertility?

Although there have been reports of declining male fertility in the US and in Europe, several recent studies have not found a drop in sperm counts over the past 50 years. A large 2000 study based in Los Angeles, for example, found virtually no change in sperm count from a study conducted in the 1950s. Similarly, a Danish study showed no change in sperm quality in men born between 1950 and 1970.

Some experts suggest that the decline observed in other studies may not have taken into consideration normal sperm fluctuations that can occur from year to year and from season to season. Sperm counts also appear to differ by region.

Temperature and climate, then, may play some role in the differences seen from country to country and from year to year. In one study, Finland had the highest measured sperm count in the world, while Britain's was low. (It should be noted that a more recent study has reported a significant decline in sperm count in Finnish men between 1981 and 1991.) In another study, the sperm count in New York City was much higher than that in Los Angeles.
Note: Many studies are limited, and most rely on data from sperm banks, which also may not reflect the male population as a whole.