In the Danish city of Aarhus, a big university town by the sea, young men stream into the offices of Cryos International each day to fill a cup with their semen – so many that there's a 600-person waiting list. Guinness World Records lists it as the planet's largest sperm bank: It has 140,000 samples available, ships to more than 65 countries and helps to impregnate close to 2,000 women a year.
International headlines have compared it to the new Viking invasion: “How Danish Sperm is Conquering the World,” said one; another, “the Viking Baby Boom.” Yet beneath the big horns and bravado, there has been more fretting in Denmark over the future of manhood than in most places on Earth.
One reason they are such avid sperm donors is that their own country is in need: Danes have among the world's lower sperm counts. They also have one of the highest rates of assisted reproduction (more than 8 per cent of births), testicular cancer and male genital abnormalities.
If the sperm story in a tiny country like Denmark can appear to have two very different sides, it's no wonder that it has become an epic saga of confusion and conflict in the rest of the world.
It was Danish scientists who first reported in 1991 that sperm counts were in free fall around the globe. They announced counts had dropped by an alarming 50 per cent worldwide between 1938 and 1990 and predicted the trend would continue, painting a picture so bleak it suggested all men were on the road to sterility.
Many scientists hammered the study as flawed, but the news went off like a bomb in the news media, igniting debates over a long, worrisome list of possible causes, from estrogen exposure to toxic chemicals to long car trips and tight pants.
Yet 20 years later, despite everything riding on it – male sexual health and the very survival of the species – researchers are split over whether it's true.
“We don't even have consensus about what determines quality sperm – is it density, shape, total number? … Is it big head movement, or big tail movement? It's like comparing apples and bananas,” says Ole Schou, founder of Cryos. “But everybody in the general population thinks there's something wrong with sperm.”
“This area is a mess,” says Keith Jarvi, head of urology at Mount Sinai Hospital in Toronto. “The only consensus is we really don't know.”
Some experts think things are looking up; others still fear that society may face the kind of apocalyptic scenario depicted in Children of Men, the 1992 P.D. James novel and 2006 film about a chaotic, wartorn world of humans unable to procreate. (The novel was in fact inspired by reports of falling sperm counts.)
It's a long route from the day that pure curiosity drove a 17th-century Dutch scientist to peer down his homemade microscope at the fluid he had captured from a conjugal romp.
Anton Van Leeuwenhoek worried that his descriptions of the wee creatures he saw swimming vigorously might “disgust or scandalize the learned.” But the Royal Society of London took a longer view and published his descriptions of spermatozoa, the “sperm animals” he saw, as well as his hunch that sperm had something to do with fertility – even though many people for the next hundred years thought they were parasites.
Only in the 19th century were sperm recognized as the cellular seeds of male fertility. And soon after, people started counting them as a measure of such – in frogs, roosters and, eventually, men. By the 1930s, studies had stacked up enough to define a normal range, which led to international comparisons. It was in October, 1991, at a World Health Organization meeting on environment and reproductive health that researchers at the University of Copenhagen shocked the world with theirs.
Tracking sperm counts of nearly 15,000 fertile men published in 61 studies over 50 years, researchers led by Niels Skakkebaek found sperm concentration in human semen had fallen worldwide by nearly half – a progression they depicted with a dark line sloping down through the decades.