A sprawling international fertility scandal is forcing regulators and doctors across Europe to rethink donor screening after a single sperm donor — whose genetic material helped conceive nearly 200 children — was later found to carry a dangerous mutation tied to aggressive childhood cancers.
According to Fox News, for nearly two decades, clinics across the continent relied on sperm from the unidentified donor, who began donating as a student in 2005.
His samples were sent from Denmark’s European Sperm Bank (ESB) to 67 fertility centers in 14 countries.
During that time, he passed standard health checks and showed no signs of genetic illness.
But hidden in a portion of his sperm cells was a mutation affecting the TP53 gene — a critical guardian of the body’s DNA. When functioning properly, TP53 repairs damaged cells or destroys them before they can become cancerous. When broken, the protection disappears.
Researchers say the donor’s mutation likely appeared spontaneously in his reproductive cells, meaning it never showed up in typical screenings and posed no danger to him or his family.
Yet up to 20% of his sperm carried the harmful variant. Every child conceived from one of those affected cells inherited the mutation in every cell of their body.
Many of those children now face a 90% lifetime risk of developing cancers associated with Li-Fraumeni syndrome — a condition marked by breast cancer, brain tumors, bone cancers and leukemia.
Doctors presented the case in May at the European Society of Human Genetics conference.
French cancer-genetics specialist Edwige Kasper told attendees that at least 23 children had already been confirmed to carry the mutation. Ten had been diagnosed with cancer. Several had died young.
“This is the abnormal dissemination of genetic disease,” Kasper warned. “Not every man has 75 children across Europe.”
Because not all records have been gathered, the BBC-led investigation that uncovered the case estimates that the real number of affected children could be far higher, as 197 births are linked to the donor’s sperm.
Kasper urged European nations to set strict limits on the number of families a single donor can help create. The European Society of Human Reproduction and Embryology recently recommended a cap of 50 families per donor.
She also advised immediate genetic counseling for all families who used the donor’s sperm.
“We have some children that have already developed two different cancers, and some of them have already died at a very early age,” she said.
The ESB issued a statement expressing “deepest sympathy” for the families and insisting it followed established medical standards. The bank emphasized that the TP53 mutation was confined to a small portion of the donor’s sperm cells — a type of mosaicism that typical screening cannot detect. Once the mutation was confirmed in 2023, the donor was blocked and clinics were notified.
“Donors should be healthy and have no history to suggest hereditary disease,” the bank said. But it added that clinics, not sperm banks, are responsible for informing patients.
Experts say the case underscores how modern fertility systems can inadvertently magnify a rare genetic defect. Fox News medical analyst Dr. Marc Siegel said it highlights the need for stronger and more modern safeguards.
“This awful story emphasizes the growing need for up-to-date genetic screening for all donors,” he said, adding that emerging AI tools could help detect mutations faster and more reliably.
The American Society of Reproductive Medicine echoed the call, reiterating its guidance that donors undergo “appropriate genetic evaluation.”
Parents affected by the discovery are being advised to immediately contact their fertility clinic or national reproductive-medicine authority for next steps — and, for many, answers they never expected to seek.
