In recent years, sperm has been shipped out of Denmark at an astonishing rate, producing thousands of babies worldwide - many in the UK. In 2006, the UK was not importing any Danish sperm, but by 2010 Denmark was supplying around a third of our total imports. Why are Danish donors in such demand? Is it simply a desire for the tall, blonde, blue-eyed, well-educated stereotype - or is there more to it?

Kate Brian, who has reported on fertility issues for two decades, hears from women who have been attracted by the range and availability of Danish donors. Some have been overwhelmed by the vast amount of detail that can be accessed online – typically, thirty pages about each individual, including voice samples and baby photos.

She investigates whether there is a problem with the UK's own system of recruiting and supplying donor sperm. One couple looked to Denmark after being told there was a 10-year wait in their area for a suitable donor. How common is this? Has the 2005 law change removing UK donors' rights to anonymity made a difference?

Kate also travels to Copenhagen to meet some of the 250 men who regularly donate at European Sperm Bank, receiving around £30 per visit. How rigorous is the selection process for becoming a donor? Is the incentive merely financial? And how do the men feel about producing potentially hundreds of children, many of which may contact them in years to come?

(Photo: Vials of sperm are frozen at Cryos, the world's biggest sperm bank, in Aarhus, Denmark. Credit: Slim Allagui/AFP/Getty Images) Show less