A sperm donor with a hidden cancer gene fathers almost 200 children and their families are surprised

A sperm donor whose samples helped conceive nearly 200 children across Europe unknowingly carried a genetic mutation that causes cancer, a hidden risk now linked to multiple childhood diseases and premature deaths.

An investigation led by the BBC and many other public service broadcasters revealed that donations were made to the European Sperm Bank (ESB) in Denmark, and was then used by 67 fertility clinics in 14 countries over a period of 17 years.

The donor, who was not identified, was paid to donate as a student beginning in 2005, according to the report.

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Although the donor passed initial health screenings, he had hidden genetic mutations that damaged the TP53 gene, which helps prevent cancer by repairing DNA damage or triggering the death of cancer cells.

When TP53 is mutated, those protective functions are lost, which can lead to uncontrolled cell division, accumulation of mutations and tumor growth, research has shown.

Up to 20% of the man’s sperm would contain that mutated gene, and any child conceived from that affected sperm would have the mutation in every cell of his body, the BBC report stated.

As a result, these children would have a 90% risk of developing some type of cancer throughout their lives, including breast cancer, bone cancer, brain tumors and leukemia. This increased risk is known as Li Fraumeni syndrome.

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Doctors raised these concerns at the annual congress of the European Society of Human Genetics (ESHG), which was held in Milan in May 2025.

At that conference, Edwige Kasper, a cancer genetics specialist at Rouen University Hospital in France, presented the case of the sperm donor whose genetic material carried the harmful variant.

“This is an abnormal spread of genetic diseases. Not all men have 75 children throughout Europe.”

It was reported that at that time 23 children had been confirmed to have the variant, 10 of whom had already been diagnosed with cancer. The real number is likely much higher, the report surmised, as at least 197 children were born from donated sperm, but not all data has been collected.

Kasper called for a limit on the number of single-donor births or families in Europe.

“We can’t sequence the entire genome of all sperm donors; I’m not advocating that,” he said. “But this is an abnormal spread of genetic diseases. Not all men have 75 children throughout Europe.”

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He also recommended that children born from this donor’s sperm undergo genetic counseling.

“We have some children who have already developed two different types of cancer, and some of them have already died at a very young age,” Kasper recently told researchers.

There is no global law that limits how many times a donor’s sperm can be used or how many children can be born from a single donor, according to the European Society of Human Reproduction and Embryology (ESHRE).

However, each country may have its own rules or guidelines regarding the use of sperm donors. The ESHRE recently proposed an international limit of 50 families per donor.

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Dr. Marc Siegel, News senior medical analyst, commented on these developments to News Digital.

“This horrific story emphasizes the growing need for up-to-date genetic testing for all donors,” he said. “It also provides context for the idea that knowing the donor provides an advantage.”

“Genetic screening, including screening for oncogenes (genes that have the potential to cause cancer), is improving dramatically, and any use of sperm donations should include it,” Siegel continued. He also called for AI to be used to improve and speed up the process.

“When a susceptibility to the disease is suspected, the sperm should be discarded,” the doctor added.

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In a statement sent to News Digital, the European Sperm Bank expressed its “deepest condolences” to the families involved.

“We are deeply affected by the case and the impact that the rare TP53 mutation has on several families, children and the donor. They have our deepest condolences,” the ESP said.

“ESB tests and performs an individual medical evaluation of all donors in full compliance with legislation and recognized scientific practice.”

In the case of this particular sperm donor with the TP53 mutation, the ESB observed that it occurs only in a small part of the donor’s sperm cells and not in the rest of the body.

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“In such cases, the donor himself and his relatives are not sick and such a mutation is not detected preventively by genetic testing,” the agency stated.

When the ESB later confirmed the mutation in 2023, the donor was “immediately blocked” and authorities and clinics were notified.

“The donor and his relatives are not sick and such a mutation is not detected preventively by genetic screening.”

“Clinics are responsible for informing patients, in part because we, as a sperm bank, do not necessarily know the patients, and because the patients’ own treating physicians are best prepared to advise them on the specific situation,” the agency stated.

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When contacted by News Digital, the American Society for Reproductive Medicine (ASRM) provided its guidance on embryo and gamete donation, which stated in part that all potential donors should undergo “appropriate genetic evaluation.”

“Donors must be healthy and have no history suggesting hereditary diseases,” the ASRM continued.

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Parents with concerns are encouraged to contact both the clinic treating them and the relevant fertility authority in that country.