Scientists and physicians agree that there's been a general decline in male fertility -- but they aren't sure why. Social media buzz has pointed to a few environmental exposures as potential factors, including cellphones and electric vehicles.

About 1 in 10 couples struggles to get pregnant within a year, which is the clinical definition of infertility. The issue is becoming more common due to delayed parenthood, increased obesity, environmental toxin exposure and underlying health conditions like endometriosis and sexually transmitted infections.