SPERM DONOR WITH CANCER-CAUSING GENE FATHERED AT LEAST 197 CHILDREN

PEOPLE

 

Sperm Donor with Cancer-Causing Gene Fathered at Least 197 Children, Says Report

Some children have already died and only a minority who inherit the mutation will escape cancer, a new report stated on Wednesday, Dec. 10

By Becca Longmire  Published on December 10, 2025 09:02AM EST

 

Nearly 200 children have been conceived by sperm from a donor carrying a gene that dramatically increases the risk of developing cancer, according to a report.

 

A major investigation released by the BBC confirmed that the sperm had been sold to families across Europe by Denmark's European Sperm Bank (ESB). The anonymous donor is thought to have fathered at least 197 children, per the outlet.

 

The man in question, who first started donating sperm when he was a student in 2005, is thought to be healthy and passed the donor screening checks, the BBC noted. However, it has since been revealed that the DNA in some of his cells mutated before he was born, damaging the TP53 gene.

 

Per the Cleveland Clinic, TP53 is among the "tumor suppressor genes," which help "protect your body from cancer."

 

"They do that by managing cell growth. When these genes change — or mutate — your cells may multiply uncontrollably and become tumors," the Clinic adds.

 

The BBC noted that some children had already died and only a minority who inherit the mutation will escape cancer during their lifetimes.

 

The report added that up to 20 percent of the donor's sperm contains the gene, adding that any children made from the affected sperm will have the mutation in every cell of their body, which is known as Li Fraumeni syndrome.

 

This is "a rare hereditary disorder that increases the risk [that] you and your family members will develop cancer," the Cleveland Clinic states.

 

"Li-Fraumeni syndrome can’t be prevented. But early and consistent cancer screenings and treatment can limit the syndrome’s impact on your life and your family’s lives," the Clinic adds.

 

The investigation into the sperm donor — which has been conducted by 14 public service broadcasters, including the BBC, as part of the European Broadcasting Union's Investigative Journalism Network — stated that the man's sperm had been used by women for around 17 years.

 

The ESB said in a statement obtained by PEOPLE, "We are deeply affected by the case and the impact that the rare TP53 mutation has on a number of families, children and the donor. They have our deepest sympathy."

 

"ESB tests and performs an individual medical assessment of all donors in full compliance with recognized and scientific practice and legislation," the statement added.

 

"In this specific case, it is a new, previously undescribed TP53 mutation. It occurs as a gonadal mosaicism, i.e. only in a small part of the donor's sperm cells and not in the rest of the body," the ESB continued.

 

They went on, "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. When we suspected and later confirmed a gonadal mosaicism in 2023, the donor was immediately blocked and we notified authorities and clinics in accordance with the law."

 

"The clinics are responsible for informing the patients, partly because we as a sperm bank do not necessarily know the patients, and because the patients' own treating physician are best equipped to advise them in the specific situation," the statement concluded.

 

Concerns about the mutation had been raised earlier this year by the European Society of Human Genetics (ESHG), per a release obtained by PEOPLE.

 

PEOPLE previously reported news of the findings when Dr. Edwige Kasper, a French biologist, presented the case at the ESHG conference in Milan back in May.

 

Sixty-seven children from 46 families in eight European countries were tested, with the variant being found in 23 of them and cancer found in 10 to date, the release noted at the time, adding that some of the children had been diagnosed with leukemia and non-Hodgkin lymphoma.

 

“The follow-up protocol involves whole-body MRI scans, MRI scans of the brain and, for adults, of the breast, ultrasound examination of the abdomen, and a clinical examination by a specialist," Dr. Kasper — who works as a cancer geneticist at Rouen University Hospital in France — said, per the release.

 

"This is heavy and stressful for carriers, but we have seen its effectiveness in that it has enabled early detection of [tumors] and thus improved patients’ chances of survival,” she continued.

 

The laws on sperm donation "differ from one European country to another," the ESHG release stated.

 

"Private sperm banks usually limit donation from one donor to 75 countries worldwide. The law in France sets a limit of ten births per donor," the ESHG said.

 

"However, in addition, there can be up to 15 births in Germany and in Denmark, and in the U.K. the same donor may be used for 12 and 10 families, respectively. At a European or international level this can represent a large number of births," the release continued.

 

Dr. Kasper insisted of the TP53 case in the release, "We need proper regulation at European level to try to prevent it happening again, and to implement measures to ensure a worldwide limit on the number of offspring conceived from the same donor.”

 

She then told the BBC of the investigation, "We have many children that have already developed a cancer. We have some children that have developed already two different cancers and some of them have already died at a very early age."

 

The ESB said in a statement obtained by PEOPLE, "Unfortunately, we have identified that the limits for how many families a donor can be used for have been exceeded in some countries both in the specific case regarding TP53 and in other cases. This is partly due to inadequate reporting from the clinics, non-robust systems and fertility tourism. We are in dialogue with the authorities in Denmark and Belgium about this."

 

The company insisted it had "continuously improved its control mechanisms to support the existing online reporting tools that have been available to clinics."

 

The U.K.'s Human Fertilisation and Embryology Authority (HFEA) confirmed that "a very small number of U.K. women" had traveled to Denmark for the donor's sperm.

 

Peter Thompson, Chief Executive of the HFEA, said in a statement, “We can confirm that the Danish Patient Safety Authority has informed us that a very small number of U.K. women have been treated in Danish Fertility clinics with this sperm donor. We understand that they have been told about the donor by the Danish clinic at which they were treated."

 

"As the U.K. regulator, we only collect or hold information about treatment which takes place in the U.K.,” he pointed out in the statement, which was also obtained by PEOPLE.

 

The ESB insisted of the investigation in a statement obtained by PEOPLE, "It is important, especially in light of this case, to remember that thousands of women and couples do not have the opportunity to have a child without the help of donor sperm."

 

"Potential donors are screened intensively, and only about [five] percent of the men who want to be donors are approved by ESB. Thus, it is generally safer to have a child with the help of donor sperm if the sperm donors are screened according to medical guidelines and current legislation than to have a child with a man who has not been screened," they added.

 

Dr. Edwige Kasper didn't immediately respond when contacted by PEOPLE for comment.