Sperm counts worldwide plunged by sixty-two percent in under fifty years between 1973 and 2018, and this could lead to a reproductive crisis.
The research was done by an Israeli and American team joined by researchers from Denmark, Brazil, and Spain, who studied sperm count trends in areas that had not been previously reviewed.
Professor Hagai Levine of the Hebrew University of Jerusalem, who led the research, told The Times of Israel, “We should be amazed and worried by the finding.”
Associated with low sperm count, the sixty-two percent drop refers to the number of sperm present in an average ejaculation, as published in the journal Human Reproduction Update on Tuesday.
How researchers investigated the drop in sperm count
Men who checked their sperm count because of fertility problems were not included in the new study, according to Professor Levine and his colleagues.
The researchers crunched numbers from hundreds of peer-reviewed studies and adjusted overall statistics in an attempt to eliminate potentially distorting data.
A peer-reviewed study noted that during the same period, the concentration of sperm in men dropped by more than fifty-one percent on average from 101.2 million to 49 million sperm per milliliter of semen.
That number, below which men are technically deemed to have a low sperm concentration, still remains above the World Health Organization’s cutoff of fifteen million per milliliter, as reported by The Times of Israel.
Low sperm counts could threaten survival of mankind
However, according to both Professor Levine and Professor Shanna Swan at New York’s Icahn School of Medicine, the drop is, nevertheless, alarming and predictive of future trends.
The epidemiologist said, “We have a serious problem on our hands that, if not mitigated, could threaten mankind’s survival.”
He added, “We urgently call for global action to promote healthier environments for all species and reduce exposures and behaviors that threaten our reproductive health.”
The analysis doesn’t mention possible reasons for sperm declines, but other studies have tied falling sperm counts to obesity, sedentary lifestyles, smoking, and exposure to certain chemicals and pesticides among other factors.
Significant drop in sperm count among men globally
According to Euronews, the same team had already reported an alarming decline in sperm counts across the Western world in 2017.
That report claimed there was a fifty percent general decrease in sperm counts in the U.S., Europe, Australia, and New Zealand between 1973 and 2011.
Furthermore, meta-analysis looked at 223 studies from across fifty-three countries based on sperm samples from more than fifty-seven thousand men.
The sperm count concentration among men in the meta-analysis had dropped by more than fifty-one percent from 101.2 million to 49 million sperm per milliliter of semen between 1973 and 2018 in men not known to be infertile.
Low sperm counts associated with major health risks
Researchers noted that this is dismaying in general for both male fertility and for men’s health since low sperm counts usually come with increased risk of chronic disease, testicular cancer, and a decreased lifespan.
He added, “The trend of decline is very clear. This is a remarkable finding and I feel responsible [for] deliver[ing] it to the world. The decline is both very real and appears to be accelerating.”
He said, “What is more, we’re looking at averages, and if men are today averaging 50 million sperm per milliliter, there are large numbers of men who today have under 40 million sperm per milliliter—in other words, fertility that is actually suboptimal.”
Professor Swan gives more details about decline in sperm count
Professor Shanna Swan of New York’s Icahn School of Medicine reported that dropping sperm counts are part of a wider decline in men’s health.
She said, “The troubling declines in men’s sperm concentration and total sperm counts at over [one percent] each year as reported in our paper are consistent with adverse trends in other men’s health outcomes.”
“These include testicular cancer, hormonal disruption and genital birth defects, as well as declines in female reproductive health,” Swan concluded, adding that “this clearly cannot continue unchecked.”
Sperm counts expected to drop more within a decade
Far wider in geographical reach, the new study includes seven more years of statistics and covers fifty-three countries.
He added that that number is expected to be the global average within a decade at the rate of the current decline.
The epidemiologist reported that research suggests fertility starts dropping when sperm concentration goes under forty million per milliliter.