Business is booming for the world's biggest sperm bank, Denmark's Cryos, which is struggling to meet demand despite a soaring number of donors and new offices opening around the world.
At Cryos headquarters in Denmark's second-biggest city Aarhus, chief executive Ole Schou smiles broadly, sitting at his desk adorned with pictures of cheerful babies as he speaks of the company's unexpected success.
Two years ago, he was ready to shut down the business, or at least move it abroad, because of a Danish tax authority proposal that would have required donors to declare income from their donations, thereby putting their anonymity at risk.
But when it became clear that this would sound the death knell for Cryos, tax authorities withdrew the proposal.
A year later, in 2008, the number of donors had grown threefold, from 30 a day to 100 at its four Danish offices in Aarhus, Copenhagen, Odense and Aalborg, while the number of men applying to be donors had risen from 350 to around 1,000.
As a sign of its success, the sperm bank recently moved its headquarters to a 1,000-square-metre (10,760-square-foot) airy and bright office space brimming with photographs of dimple-cheeked newborns.
It has also doubled the number of employees, and sales have risen from two million euros (2.7 million dollars) in 2006 to three million in 2008.
Jesper, a 28-year-old medical student, walks out of the building. He tells AFP that he decided to become a donor after watching a programme on television about infertile couples.
"My girlfriend is pregnant and she suggested that I should be a donor to help others," he says, refusing to divulge his family name.
Hans, a 38-year-old electrician who has children of his own, has a similar explanation.
"I do it to do a good deed, but also for the money," he says, explaining that he gets paid 600 kroner (80 euros, 110 dollars) per donation for his "very good quality" sperm.
Each year, Cryos exports 85 percent of its 15,000 to 20,000 sperm donations to more than 400 clinics in 60 countries.
But despite the rising number of donors, Cryos has a hard time meeting demand.
Around 10 to 15 percent of couples in the world are infertile, according to Schou. Added to that are single women nearing the end of their childbearing years who still want to have a family.
"We help a tsunami of highly-educated single women who are more demanding and who prioritised their careers and who want to have a child before it is too late," Schou says.
The phenomenon has surged in the past three or four years, and Cryos "can't meet the avalanche of demand from the western world, in particular the United States."
Laws that bar anonymous sperm donations in nearby countries like Sweden, Britain, The Netherlands, Austria and Germany have also led to a rise in "fertility tourism, where women visit clinics in other countries to be inseminated, like French women who go to Belgium and Swedes who go to Denmark," Schou says.
A 55-year-old economist, Schou started the sperm bank in a tiny cellar office in 1987 out of a desire to help couples who couldn't have children.
Cryos, which means "freeze" in Greek and refers to the sperm conservation process, was originally started to help cancer patients who wanted to freeze their sperm before undergoing chemotherapy. Since 1991 it has focused on providing sperm to fertility clinics worldwide.
Schou insists that the key to his company's success is its top-notch selection process which yields high quality sperm.
"A high quality sperm provided in the best safety conditions, a body of 335 donors and technology that enables us to offer a competitive product in the requested time frame," he boasts.
Cryos' sperm has produced more than 14,000 full-term pregnancies since 1991, and the company has received piles of letters of thanks from women around the world, Schou says.
And while the sperm from a Danish Viking with blond hair and blue eyes may be exactly what clients are looking for in northern Europe, it "is far from the ideal in other parts of the world."
"That's why we've opened a franchise in New York and another one in Bombay, in India."
In the next five years, Cryos plans to open up to 10 new offices, expanding further in Europe, Asia, Africa and Australia to give it a broad ethnical donor base to meet the demands of people all around the world.
Cryos chief doctor, Gert Bruun Petersen, heads a team that "sorts through the list of possible donors, discarding more than two-thirds mainly because of their sperm quality."
He says he dreams of seeing "all children born with Cryos sperm born 100 percent healthy."
Clinical studies show there are 15 to 20 cases per year of Cryos offspring born with malformations, representing about four percent of all donors.
"It's important for us to identify the donor whose sperm led to malformations as quickly as possible to limit the problem and determine if it is a genetic disorder," Petersen says.
The ideal would be to "examine the entire genetic mass" of a donor in order to prevent birth defects. "But that's mission impossible today," he says.
In addition to selling sperm to clinics, Cryos recently began direct sales to the public in order to meet the demands of some clients.
It set up a catalogue of 50 donors, including 44 who remain anonymous, on its website, listing donors' profiles with their IQ, childhood photographs, hobbies, school grades and other personal information.
Buyers can select the sperm of the donor that most appeals to them -- not an option at clinics, where sperm quality is the only determining factor -- and buy it online for up to 8,000 euros.
The initiative has been heavily criticised in Denmark, where opponents argue that sperm should not be handled like a supermarket product.
Among Cryos' donors, around 20 percent have chosen to not be anonymous. Their average age is 32, while that of anonymous donors is between 23 and 25 years.
"They may be interested in having contact with their offspring, and may not be as altruistic as the anonymous donors. They may have other motives, ulterior motives that are more egotistical," says Schou.
And there is a market for donors who can be traced.
Contrary to heterosexuals, he explains, "lesbians and single women often prefer this kind of donor because they know their children will one day want to know who their biological father is."