'Spermageddon': global decline in sperm count could threaten humanity
'Drastic shift' linked to environmental factors including pollutants and chemicals, and lifestyle issues such as obesity
Men's sperm counts have more than halved over the past 50 years, with potentially drastic consequences for the future of the human race.
About one in six adults worldwide experience infertility at some point, according to the World Health Organization, and between 30% and 50% of cases are linked to problems with the quantity and quality of semen, said New Scientist. Either the total number of sperm is too low, or the cells "struggle to swim" (reduced motility), which decreases the chance of reaching an egg cell.
The big question is no longer "whether this so-called 'spermageddon' is happening", said science writer David Robson, "but why, and what to do about it".
Subscribe to The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.
Sign up for The Week's Free Newsletters
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
What is 'spermageddon'?
The "drastic shift" in sperm counts has been documented since the 1970s, but by the 1990s "the issue started catching considerably more scientific attention", said Robson.
In 2017, veteran reproductive epidemiologist Shanna Swan and her team at the Icahn School of Medicine at Mount Sinai, New York, published a meta-analysis of 185 studies of more than 42,000 men between 1973 and 2011: "the largest of its kind", said Robson.
The results showed that the concentration of sperm in a millilitre of semen, and the total number of sperm in the sample, seemed to have decreased by 50%-60% in men from North America, Europe and Australasia. "If the decline continued at this rate, the median sperm count would reach zero by the mid-2040s," said Robson.
The team followed up with new data from South America, Asia and Africa in 2022, controlling for potential reporting bias and changing technology, and reported a decline on every continent.
The decline, they warned, had the potential to "threaten mankind's survival", said The Times.
Why is this happening?
"Various features of modern life have been posited as potential causes," said Forbes, including pollution, alcohol and drug use, increasing temperatures due to global warming, stress, poor diet, sedentary lifestyle and exposure to chemicals like pesticides.
Swan's team particularly highlighted pollutants called endocrine-disrupting chemicals, or EDCs, found in some plastics and pesticides.
Other studies found a link between obesity and a lower sperm count with reduced sperm motility. Excess body fat could cause inflammation that disturbs the hormonal balance necessary to produce sperm, Albert Salas-Huetos, a researcher at the University of Rovira i Virgili in Spain, suggested.
One eye-catching study, published in the Fertility and Sterility journal last year, found "significant exposure-response trends" between decreased sperm count and concentration, and "increasing frequency of mobile phone use". Men between the ages of 18 and 22 who said they used their phones more than 20 times a day had a 21% higher risk of a low overall sperm count, said CNN.
Nutrition could also be a factor, with one 2019 study finding that men who regularly consumed fruit, vegetables, nuts and fish had higher sperm concentrations, with greater motility, compared with those with less balanced diets.
Viruses are increasingly under the microscope, with a study in 2022 finding that Covid-19 infections reduced sperm counts and motility.
Interestingly, however, one study that analysed data measuring the sperm of dogs, between 1988 and 2014, found a comparable decline to humans.
What are the potential consequences?
It isn't yet clear how important a decline in sperm is for "overall fecundity", said Robson. Despite "large variation" in sperm count among healthy men, "the absolute figures don't seem to make a big difference to the chances of conception until they dip below a very low threshold".
But much of the chemical pollution that harms fertility is also leading to more babies being born with reproductive disorders, according to Swan. It increases the likelihood of undescended testes, genital malformations and smaller penises. There is also a link between reduced sperm counts and rising rates of testicular cancer among young men.
The good news, said Euronews, is that at least some of the damage is reversible – "provided we take action". Healthy, balanced diets, weight loss and quitting smoking can all lead to increased sperm counts.
Sign up for Today's Best Articles in your inbox
A free daily email with the biggest news stories of the day – and the best features from TheWeek.com
Harriet Marsden is a writer for The Week, mostly covering UK and global news and politics. Before joining the site, she was a freelance journalist for seven years, specialising in social affairs, gender equality and culture. She worked for The Guardian, The Times and The Independent, and regularly contributed articles to The Sunday Times, The Telegraph, The New Statesman, Tortoise Media and Metro, as well as appearing on BBC Radio London, Times Radio and “Woman’s Hour”. She has a master’s in international journalism from City University, London, and was awarded the "journalist-at-large" fellowship by the Local Trust charity in 2021.
-
The Onion is having a very ironic laugh with Infowars
The Explainer The satirical newspaper is purchasing the controversial website out of bankruptcy
By Justin Klawans, The Week US Published
-
'Rahmbo, back from Japan, will be looking for a job? Really?'
Instant Opinion Opinion, comment and editorials of the day
By Justin Klawans, The Week US Published
-
What's next for electric vehicles under Trump?
Today's Big Question And what does that mean for Tesla's Elon Musk?
By Joel Mathis, The Week US Published
-
Has the Taliban banned women from speaking?
Today's Big Question 'Rambling' message about 'bizarre' restriction joins series of recent decrees that amount to silencing of Afghanistan's women
By Harriet Marsden, The Week UK Published
-
Cuba's energy crisis
The Explainer Already beset by a host of issues, the island nation is struggling with nationwide blackouts
By Rebekah Evans, The Week UK Published
-
Putin's fixation with shamans
Under the Radar Secretive Russian leader, said to be fascinated with occult and pagan rituals, allegedly asked for blessing over nuclear weapons
By Harriet Marsden, The Week UK Published
-
Chimpanzees are dying of human diseases
Under the radar Great apes are vulnerable to human pathogens thanks to genetic similarity, increased contact and no immunity
By Harriet Marsden, The Week UK Published
-
Deaths of Jesse Baird and Luke Davies hang over Sydney's Mardi Gras
The Explainer Police officer, the former partner of TV presenter victim, charged with two counts of murder after turning himself in
By Austin Chen, The Week UK Published
-
Quiz of The Week: 24 February - 1 March
Puzzles and Quizzes Have you been paying attention to The Week's news?
By Sorcha Bradley, The Week UK Published
-
Will mounting discontent affect Iran election?
Today's Big Question Low turnout is expected in poll seen as crucial test for Tehran's leadership
By Sorcha Bradley, The Week UK Published
-
Sweden clears final NATO hurdle with Hungary vote
Speed Read Hungary's parliament overwhelmingly approved Sweden's accession to NATO
By Peter Weber, The Week US Published