Men's Sperm Counts Fall Drastically, Worldwide
In less than 40 years, sperm counts—the best measure of male fertility currently available—have declined more than 50 percent in men in North America, Europe, Australia, and New Zealand. Results of a meta-analysis of thousands of previous studies published in the journal Human Reproduction Update revealed that alarming statistic, and also found that the drop does not seem to be leveling off.
Researchers reviewed 7,500 studies and selected 185 that met their criteria—those involving men whose fertility was unknown and men known to be fertile. They excluded studies involving men with suspected or confirmed fertility issues.
What they found was that from 1973 to 2011, sperm concentration and total sperm count in men from Western countries fell by more than 50 percent. While they didn’t provide an explanation for this decline, researchers noted theories including environment and lifestyle factors such as prenatal and lifetime chemical exposures, smoking, higher stress levels, and increasing rates of obesity.