Sperm Donor’s Hidden Genetic Mutation Linked to Cancer in Nearly 200 Children Across Europe

A widespread public health crisis is unfolding across Europe as investigators have discovered that a single sperm donor, whose samples helped conceive nearly 200 children, unknowingly carried a dangerous cancer-causing genetic mutation. This hidden risk has already been tied to multiple childhood illnesses and early deaths among the affected offspring.

A joint investigation led by the BBC and several other public service broadcasters revealed that the donations were made to Denmark’s European Sperm Bank (ESB) and subsequently distributed to 67 fertility clinics across 14 European countries over a 17-year period. The donor, who remains unidentified, began providing samples as a student in 2005.

Although the donor passed initial health screenings, he carried hidden genetic mutations that damaged the TP53 gene—a critical component in preventing cancer development. The TP53 gene normally helps repair DNA damage and triggers the death of cancer cells. When mutated, these protective functions are compromised, potentially leading to uncontrolled cell division and tumor growth.

According to the investigation, approximately 20% of the man’s sperm contained the mutated gene. Children conceived from affected sperm would have this mutation present in every cell of their bodies, resulting in Li Fraumeni syndrome—a condition that carries a staggering 90% lifetime risk of developing various cancers including breast cancer, bone cancers, brain tumors, and leukemia.

Edwige Kasper, a specialist in cancer genetics at Rouen University Hospital in France, presented this alarming case at the annual congress of the European Society of Human Genetics in Milan in May 2025. At that time, 23 children had been confirmed to carry the variant, with 10 already diagnosed with cancer.

“We have some children that have already developed two different cancers, and some of them have already died at a very early age,” Kasper told investigators.

The actual number of affected children is likely much higher, as at least 197 children were born from the donated sperm, but comprehensive data collection remains ongoing. This scenario has prompted Kasper to call for limitations on the number of births or families for a single donor in Europe.

“We can’t do whole-genome sequencing for all sperm donors—I’m not arguing for that,” she said. “But this is the abnormal dissemination of genetic disease. Not every man has 75 children across Europe.”

Currently, no global regulation limits how many times a donor’s sperm can be used or how many children may be born from a single donor, according to the European Society of Human Reproduction and Embryology (ESHRE). Individual countries may have their own regulations, but the lack of international standards has allowed for this widespread distribution. In response to cases like this, ESHRE recently proposed a cap of 50 families per donor as an international limit.

Dr. Marc Siegel, Fox News senior medical analyst, emphasized the urgent need for improved screening protocols. “This awful story emphasizes the growing need for up-to-date genetic screening for all donors,” he said. “It also provides context for the idea that knowing the donor provides an advantage.”

Siegel recommended implementing advanced technologies to enhance safety measures. “Genetic screening, including for oncogenes (genes that have the potential to cause cancer) is improving dramatically, and all use of sperm donations must include it,” he noted, also suggesting that artificial intelligence could improve and accelerate screening processes.

The European Sperm Bank expressed “deepest sympathy” for the families affected by this situation. In a statement, the ESB explained that the mutation occurs only in a small portion of the donor’s sperm cells and not in the rest of his body, making it particularly difficult to detect.

“In such cases, the donor himself and his family members are not ill, and a mutation of this type is not detected preventively by genetic screening,” the agency stated. Once the mutation was confirmed in 2023, the donor was “immediately blocked” and authorities and clinics were notified.

The American Society of Reproductive Medicine’s guidance states that all prospective donors should undergo “appropriate genetic evaluation” and that “donors should be healthy and have no history to suggest hereditary disease.” Parents with concerns are encouraged to contact both their treating clinic and the relevant fertility authority in their country.

This case highlights the growing challenges in reproductive medicine as technology advances faster than regulation, leaving families to deal with unforeseen genetic consequences that may span generations.