A shocking case of a Danish sperm donor, which resulted in birth of babies with cancer in European countries, including in Greece, has revealed that many of the recipient women wanted “the Viking sperm”, the BBC reports.

The case reportedly first emerged in Greece when a local paediatrician detected a cancer-linked genetic mutation in three children of the same family born through IVF with the man’s sample.

Denmark plays a central role in the global sperm market, hosting some of the world’s largest sperm banks. The country has earned a reputation for so-called “Viking sperm,” with Cryos International founder Ole Schou attributing its success to both a strong donation culture and genetic traits. He argues that blond hair and blue eyes are recessive characteristics, making Danish sperm attractive to women from a wide range of genetic backgrounds. According to Schou, 60% of requests come from single, educated women in their 30s.

Cross-border sperm distribution, however, has highlighted serious regulatory gaps. A donor at the centre of a recent investigation provided samples to 67 clinics in 14 countries, with each state applying different limits on the number of children or families allowed per donor. As a result, a single man can legally father hundreds of children without his knowledge.

Following the revelations, Belgian authorities called on the European Commission to establish a European sperm donor registry, while Belgium’s deputy prime minister described the sector as a “Wild West.” At the same time, the European Society of Human Reproduction and Embryology has proposed an EU-wide cap of 50 families per donor.

Concerns extend beyond health risks to issues of identity and psychological impact for both children and donors, particularly at a time when DNA testing and social media make it easier to trace biological relatives. Bioethicist John Appleby has described the situation as a “huge ethical minefield,” highlighting the need to balance the desire to form families with the protection of all those involved.

The question that remains is whether — and how — meaningful oversight can be imposed on a globalised market without driving prospective parents toward informal, unregulated and ethically contentious alternatives.