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."