A sperm donor whose samples helped conceive nearly 200 children across Europe unknowingly carried a cancer-causing genetic mutation — a hidden risk now tied to multiple childhood illnesses and early deaths.

An investigation led by the BBC and many other public service broadcasters revealed that the donations were made to Denmark’s European Sperm Bank (ESB). Those donations were then used by 67 fertility clinics in 14 countries over a 17-year span.

The donor, who was not identified, was paid to donate as a student beginning in 2005, according to the report.

Although the donor passed the initial health screenings, he had hidden genetic mutations that damaged the TP53 gene, which helps to prevent cancer by repairing DNA damage or trigger the death of cancer cells.

When TP53 is mutated,

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