By Comfort Asemota
A sperm donor who unknowingly carried a dangerous genetic mutation linked to an extremely high cancer risk has fathered nearly 200 children across Europe, triggering alarm among fertility regulators, medical experts and affected families.
The donor—who appeared healthy and had no known medical conditions—carried a mutation in approximately 20% of his sperm affecting the TP53 gene, a crucial tumour-suppressor responsible for preventing cancerous cell growth. Children conceived with sperm carrying this defect have inherited Li-Fraumeni syndrome, a rare genetic disorder that gives carriers up to a 90% lifetime risk of developing cancer, often beginning in childhood.
197 Known Births, Possibly More
The Human Fertilisation and Embryology Authority (HFEA) confirmed that a small number of British women were among those who travelled abroad and received the donor’s sperm. The BBC uncovered the case in a joint investigation with 13 public service broadcasters under the European Broadcasting Union’s Investigative Journalism Network.
According to the investigation, the donor’s sperm was distributed to 67 fertility clinics across 14 countries, resulting in at least 197 births—though the true number may be higher, as several clinics have incomplete records.
Children Already Diagnosed With Cancer
Some of the donor-conceived children have already developed cancer, and several have tragically died.
Concerns first emerged at a meeting of the European Society of Human Genetics, where Dr Edwige Kasper reported that among 67 identified children:
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23 carried the TP53 mutation
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10 had already developed cancer, including cases of multiple cancers in the same child
“We have many children that have already developed a cancer… some have developed two different cancers and some have already died at a very early age,” she said.
High-Risk Mutation With Immediate Impact
The TP53 mutation linked to Li-Fraumeni syndrome significantly increases the risk of:
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Breast cancer
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Brain tumours
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Osteosarcoma
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Soft-tissue sarcomas
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Various childhood cancers
Unlike adult-onset mutations such as BRCA, TP53 places children at immediate and lifelong risk. Affected families now require intensive medical surveillance, including frequent MRI scans and ultrasounds.
One single mother whose daughter carries the mutation said she was devastated to learn she received donor sperm “that wasn’t clean, that wasn’t safe, that carried a risk”.
Regulatory Gaps Highlighted
The HFEA confirmed that none of the donor’s sperm was used in licensed UK clinics and emphasised that UK law restricts donor sperm to a maximum of 10 families. Many countries do not enforce such limits.
In Belgium, where the limit is six families, 53 children were conceived with sperm from the same donor.
Peter Thompson, HFEA chief executive, said the Danish Patient Safety Authority notified the UK that a small number of British women received treatment at Danish fertility clinics using this donor’s sperm. Those women have since been contacted.
Mutation Was Undetectable in Standard Screening
Genetic specialists stressed that the mutation would not have been detected during routine donor screening. Because the defect occurred spontaneously before the donor’s birth and did not appear in his blood, conventional genetic tests would have shown him as healthy.
Professor Jackson Kirkman-Brown, a fertility specialist, explained that each sperm cell contains unique DNA variations, making screening for such rare mutations extremely difficult. He said the larger issue is the lack of international limits on donor usage, which allowed one man’s sperm to be used in dozens of clinics across Europe.
European reproductive health authorities are now working on establishing cross-border family limits to prevent similar incidents from happening again.
Number of Affected Children Could Rise
As more families step forward, the total number of children conceived using the donor’s sperm—and those carrying the TP53 mutation—may continue to increase. The case has raised urgent questions about international donor screening standards, regulatory oversight, and fertility clinics’ responsibilities when operating across multiple countries.
