What Does It Mean If Sperm Count Among Western Men Has Shrunk By Half Since the ’70s?

Christina Cauterucci in Double X:

Men in Western nations produce about half as many sperm per milliliter of ejaculate as their peers did in the ‘70s, according to a new research review published in Human Reproductive Update. Between 1973 and 2011, researchers found, the sperm concentration of Western ejaculate fell more than 52 percent, while the total number of sperm per semen sample fell by almost 60 percent. “If we will not change the ways that we are living and the environment and the chemicals that we are exposed to, I am very worried about what will happen in the future,” co-author and epidemiologist Hagai Levine told the BBC. Those chemicals include phthalates, which recently had their 15 minutes of fame for being present in nearly all tested brands of macaroni and cheese mixes. Phthalates get into foods by way of plastics in packaging and processing equipment, and evidence strongly suggests that they disrupt testosterone production, leading to reduced sperm counts.

Previous studies of sperm count in men over time have been called into question over concerns such as known fertility problems among participants and changing sperm-measurement techniques, which may have overestimated sperm count in earlier studies. For this new study, researchers analyzed data from 185 studies that used the same sperm-count testing procedure on nearly 43,000 men, none of whom were selected for existing infertility issues or other conditions. After correcting for age and length of time since last ejaculation, the authors noted a decline in sperm concentration among Western men from 99 million sperm per milliliter in 1973 to 47.1 million sperm per milliliter in 2011. Researchers found a limited number of studies of non-Western men, but those that did exist did not indicate a similar decline sperm concentration.

More here.