Sperm Donor With a Cancer-Causing Gene Fathered at Least 197 Kids

A man who donated significant amounts of sperm to a Danish sperm bank discovered he had a genetic mutation that increases the risk of childhood cancers. Some of these children have been diagnosed with two types of cancer, while others have already died, according to the investigation.

An investigation coordinated by the EBU Investigative Journalism Network and conducted by outlets including Deutsche Welle (DW), the BBC, and other European public broadcasters has revealed that the European Sperm Bank (ESB) sold donor 7069’s sperm to women in more than a dozen countries for over 15 years. At least 197 children were conceived, and potentially many more. The ESB hasn’t released the official number due to privacy concerns.

It took two rounds of tests

The story started coming to light in 2020. The ESB was notified that doctors had diagnosed a child born from donor 7069—named Kjeld on his profile—as carrying a mutation to the TP53 gene. TP53 suppresses cancerous growth, and alterations to it result in Li-Fraumeni syndrome. The syndrome is “one of the most severe inherited predispositions to cancer†and involves a range of childhood tumors, according to a May 2025 statement from the European Society of Human Genetics.

Kjeld’s sperm was quarantined, but when genetic tests came back negative and he himself didn’t show symptoms, the quarantine was lifted, according to the investigation. The same situation repeated itself in 2023, but this time the tests revealed the TP53 mutation in some of Kjeld’s sperm. His sperm was consequently banned permanently, and the ESB began informing parents.

“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. This is heavy and stressful for carriers, but we have seen its effectiveness in that it has enabled early detection of tumours and thus improved patients’ chances of survival,†Edwige Kasper, a genetic predisposition to cancer specialist at the Rouen University Hospital, said in the statement.

Carriers of the TP53 mutation have to be monitored their entire lives, according to the investigation. The children involved are being followed attentively, according to the statement, but the investigation found that several parents weren’t officially informed that their children could carry the mutation. For example, one mother in Denmark says she learned this from another parent who had purchased Kjeld’s sperm.

Communication breakdown

She told the investigating outlets that neither the sperm bank nor her fertility clinic had reached out to her. The sperm bank is legally obligated to notify all the fertility clinics it supplies with reproductive cells of any genetic abnormalities that come to light, and the clinics are then responsible for informing parents.

In 2024, a meeting of hereditary cancer experts led many European doctors to realize that presumed individual cases were all connected, Svetlana Lagercrantz, a researcher at the Karolinska Institutet who specializes in hereditary cancers, told the investigation. As of now, doctors don’t know if all of the children have undergone testing. Some have already been diagnosed with two different cancers, and some have even passed away already, Kasper told the investigation.

“We are deeply affected by this case,†said Julie Paulli Budtz, a spokesperson for the European Sperm Bank, as reported by The Guardian earlier this year. While the donor had been tested rigorously, “it is scientifically simply not possible to detect disease-causing mutations in a person’s gene pool if you don’t know what you are looking for.â€

Part of the issue seems to be the exorbitant number of children conceived from a single unfortunate donor. According to the ESB website, most of their donors are limited to 75 families. How 197 children (at minimum) were born from the donor’s sperm is not immediately clear.

“Although the variant would have been practically undetectable in 2008 when the individual started to donate sperm, there are many things that could have been and still need to be improved,â€Â Kasper explained in the statement. “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.â€