Western men now have 50% less sperm

Study shows dramatic change over the past 40 years

The quality of sperm from men in North America, Europe and Australia has declined dramatically over the past 40 years, with a 52.4-per-cent 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.

While a number of previous studies found that sperm counts and quality have been declining, some have dismissed or criticized the studies for reasons such as the age of the men included, the size of the study and other aspects of the selection of the study population.

Some of the other concerns are outlined in an analysis published by the American Society of Andrology. The skepticism also has to do with the difficulty of comparing records from a fertility centre in the 1970s with one from today and with the fact a single man’s sperm count may fluctuate during his lifespan due to his weight, use of alcohol and many other factors. However, Shanna H. Swan, one of the authors of the new study published in the Human Reproduction Update, said that the new metaanalysis is so broad and comprehensive, involving all the published literature available in English, that she hoped it would put some uncertainty to rest.

“It shows the decline is strong and that the decline is continuing,” Swan said in an interview.

The analysis found drops only for men in Europe, North America and Australia and not for those in South America, Asia and Africa.