From Washington Post July 25, 2017
The quality of sperm from men in North America, Europe and Australia has declined dramatically over the past 40 years, with a 52.4 percent drop in sperm concentration, according to a study published Tuesday.
The research — the largest and most comprehensive look at the topic, involving data from 185 studies and 42,000 men around the world between 1973 and 2011 — appears to confirm fears that male reproductive health may be declining.