Around the developed world, sperm counts have been dropping for decades, leaving at least one in five men ages 18 to 25 "subfertile," according to a study released last month by the European Science Foundation.
While prenatal women have long been urged by doctors to improve their lifestyle to aid fertility, it appears that men haven't been holding up their end of the baby-making bargain.
"The important impact of men's reproductive health on a couple's fertility is often overlooked," said report co-author Niels Skakkebaek, according to UPI. "While poor sperm may be part of the reason more couples are using in vitro fertilization, it may also be making those therapies less successful."
Scientists attribute declining sperm counts to a variety of environmental and lifestyle factors, including chemical exposure, hard drinking and unhealthy diets, The Daily Beast reports.
Last summer, scientists observed a link between declining sperm counts and bisphenol A -- an organic compound also called BPA that can be found in some canned foods and hard plastic food containers.
It's not just the food containers that can be problematic.
And it's not just how you live -- it's where you live.
Some experts say that men who live in cities have higher sperm quality than men who live in rural areas, where men are more likely to carry traces of pesticide metabolites. (That said, country men can take solace in another recent study that indicates that men from rural areas carry a bit more below the belt than their urban counterparts.)
Read more at The Daily Beast and UPI.com.