A shocking discovery has emerged across Europe: a single sperm donor has fathered at least 197 children, some of whom have already died from cancer. The man unknowingly carried a rare mutation in a gene that dramatically increases the risk of developing multiple types of cancer.
The gene in question is TP53, which is linked to a condition called Li-Fraumeni syndrome. People with this syndrome have a 90% chance of developing cancer by age 60 and about 50% will develop cancer before turning 40, according to medical research from the Cleveland Clinic.
When the donor gave his sperm, he was completely unaware that he carried this dangerous mutation. He is healthy himself, but the genetic risk is now passed down to his children.
Initial reports in May by CNN indicated that the donor had fathered at least 67 children in eight European countries. However, a new investigation by 14 European public broadcasters, including the BBC, has revealed that the number is much higher than initially reported.
The investigation combined freedom of information requests and interviews with doctors and patients. It found that the donor had provided sperm to a single private sperm bank in Denmark, the European Sperm Bank (ESB), but his sperm was subsequently used by 67 clinics across 14 countries.
The final number of children affected could be even higher, as data is still missing from several countries. It is not yet clear how many of these children carry the TP53 mutation, but doctors warn that even a small proportion is a serious health concern.
Edwige Kasper, a biologist at Rouen University Hospital in France, first identified 67 children carrying the mutation. She presented her findings in May at the annual conference of the European Society of Human Genetics.
At that time, Kasper revealed that 10 of the children had already been diagnosed with cancers, including brain tumors and Hodgkin lymphoma, while 13 others were carriers of the gene but had not yet developed cancer.
These children will require regular medical monitoring because of their increased cancer risk. Kasper also noted that they have a 50% chance of passing the mutation to their own children.
On Wednesday, Clare Turnbull, a professor of cancer genetics at the Institute of Cancer Research in London, described Li-Fraumeni syndrome as “a devastating diagnosis to impart to a family.”
“There is a very high lifetime risk of cancer, including childhood-onset cancers,” she said.
Turnbull also emphasized how rare this case is. She explained that it is an extremely unusual coincidence: the donor carried a rare mutation affecting fewer than 1 in 10,000 people, and his sperm was used to conceive an extraordinarily large number of children.
The European Sperm Bank has responded to the discovery. Julie Paulli Budtz, a spokesperson for ESB, said the company is deeply affected by the situation and sympathizes with the families, children, and the donor.
Budtz emphasized that ESB conducts individual medical assessments of all donors in line with recognized scientific and legal standards. However, she also highlighted that there is a growing debate about limits on the number of children per donor.
“The laws differ greatly between countries, and there is a need for common, transparent European standards,” Budtz said.
Medical experts warn that families affected by this donor will face lifelong challenges. Children who carry the TP53 mutation will need frequent screenings, careful lifestyle management, and early interventions if cancer develops.
Genetic testing for Li-Fraumeni syndrome is also crucial. Experts encourage families with unexplained childhood cancers or multiple relatives with early-onset cancers to seek genetic counseling.
Some parents who used the donor’s sperm are now grappling with shock and uncertainty. For many, the news that their child may have a 50% chance of passing on a deadly gene is overwhelming.
Public health authorities in Europe are discussing how to prevent similar cases in the future, including stricter screening of sperm donors and better tracking of donor-conceived children.
The case also raises ethical questions: should there be a legal cap on the number of children per donor? And how can countries coordinate genetic safety standards across borders?
For now, families affected are left with medical, emotional, and ethical challenges, while researchers continue to track and support those at risk.
As the investigation unfolds, experts stress the importance of transparency, genetic testing, and stronger European regulations to prevent another tragedy.
This story is a reminder of the hidden risks in reproductive technologies and the profound impact a single genetic mutation can have on hundreds of lives.
