Health

Sperm Donor With Cancer-Causing Mutation Conceived 197 Children

Are urgent regulations needed to stop the spread of dangerous genetic mutations, or was this a rare exception that only requires better coordination to prevent?

Published DEC 10 2025

Sperm Donor With Cancer-Causing Mutation Conceived 197 Children

Story

Above: Eggs and sperm stored in a liquid nitrogen tank at the Fertility Center Berlin on Jan. 17, 2024. Image credit: Jens Kalaene/picture alliance via Getty Images

The Facts

A sperm donor who unknowingly carried a genetic mutation in the TP53 gene has fathered at least 197 children across Europe, according to an investigation by 14 public service broadcasters coordinated by the European Broadcasting Union’s Investigative Journalism Network.
EBU Investigative Journalism Network
Independent
GB News
The donor, referred to as “Kjeld,” began donating sperm as a student in 2005, passing all the standard screening checks at the time. Twenty percent of his sperm, however, carried a mutation linked to Li-Fraumeni syndrome, which causes up to a 90% lifetime risk of developing cancer.
EBU Investigative Journalism Network
The European Sperm Bank (ESB), based in Denmark, distributed Kjeld’s sperm to 67 fertility clinics across 14 countries over approximately 17 years before permanently blocking the donor in October 2023 after the ESB discovered the mutation.
EBU Investigative Journalism Network
Researchers uncovered that the sperm conceived at least 99 children in Denmark, 53 in Belgium and 35 in Spain. While the ESB did not sell the sperm to U.K. clinics, a small number of U.K. families used Kjeld’s sperm when travelling to Denmark for fertility treatment.
EBU Investigative Journalism Network
The News International
Telegrafi
The use of the sperm also bypassed national laws determining the number of births per donor, such as in Belgium, where the legal limit is six families per donor, which the ESB claimed was partly a result of “inadequate reporting from the clinics, non-robust systems and fertility tourism.”
EBU Investigative Journalism Network
Nos
Earlier this year, doctors identified 67 children conceived using the donor’s sperm, with 23 carrying the variant and 10 having already been diagnosed with cancer. Some children have reportedly developed multiple types of cancer, while others have already died.
The European Society of Human Genetics
BBC News
Dw.Com

Sources Split

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RIGHT

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CRIT

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ESTAB

The Spin

Narrative A

Europe’s fragmented sperm donation regulations have created dangerous loopholes that have allowed genetic diseases to spread unchecked. It is of the utmost urgency that this glaring flaw be corrected. Europe, therefore, should immediately adopt France’s medically supervised system, which offers the gold standard with its strict limits and oversight.

The European Society of Human Genetics

Narrative B

This tragedy is not indicative of systemic failures in the sperm donation industry, but rather of technical and administrative challenges in coordinating between clinics and donor banks. With the ESB having already implemented reforms to its procedures, better coordination between all parties moving forward will naturally resolve these rare issues in the future.