In some parts of the world, there has been a considerable decline in sperm quality and quantity in recent years, according to reports from sperm banks as well as evidence from scientific research. The cause is not yet known, but some are pointing pollutants and a "modern Western lifestyle," which includes cellphones in pockets, diet and a lack of physical activity.
After studying eight years worth of sperm-donor data in the Boston area, Grace Centola, a sperm bank consultant and president-elect of the Society for Male Reproduction and Urology, noted "a statistically significant decline in semen volume, sperm count and motility over those years." At a sperm bank in Israel, only 1 in 100 applicants are found suitable for donation, whereas a decade ago, using the same standards, 1 in 10 were accepted. Male infertility is suspected in about 70 percent of cases in that country.
A study published in the British Medical Journal 20 years ago found that between 1938 and 1990, sperm counts had halved (from 113 million sperm per milliliter to 66 million sperm per milliliter). A recent study in Finland revealed that men born toward the end of the 1980s had a lower sperm count than those born toward the beginning of the same decade.
Yet the numbers of births don't seem to be affected, with the human population continuing to rise. So why would this be considered a problem? Well, as Raywat Deonandan, an assistant professor and epidemiologist at the University of Ottawa, tells LiveScience, the decline could indicate that "an essential aspect of the human animal is being changed very rapidly in only a few generations."
And that's scary, because the drop in sperm quality could mean that other aspects of our health could be impacted in ways that we haven't yet detected. For example, if the decline is due to a hormonal change—like an increase of estrogen from soy plants—other parts of our bodies that are regulated by hormones, like our physical and psychological health, could be affected.
Other causes could be pollutants, high-fat diets, cellphone use, and lack of exercise. But the issue will remain unclear until studies can be done on a control group in a remote part of the world that isn't subjected to the environmental toxins and behaviors of men in more industrialized places. Until then, we'll just have to accept that semen isn't as powerful as we'd previously believed.
Image via Heather M Greig/Shutterstock
Sperm quality and quantity declining, mounting evidence suggests [MSNBC]