North American men have half as many sperm as they did 40 years ago, according to new research into reported declines in sperm counts.
The research was led by Hagai Levine, an epidemiologist who studies patterns in health conditions at the Hebrew University of Jerusalem.
Levine carried out a systematic review of 185 studies of sperm counts in 42,935 men, looking at sperm concentration and total sperm count.
He found sperm concentration among men in North America, Europe, Australia, and New Zealand declined significantly between 1973 and 2011.
In fact, men in those areas were found to have 52.4% fewer sperm than back in 1973. Total sperm count had dropped even more, declining by 59.3% since 1973.
The reason for all this isn’t clear, but researchers say “research on the causes of this continuing decline is urgently needed.”