Sperm Donor With Cancer-Causing Gene Fathered 197 Children In Europe, Alarming Investigation Reveals

A major investigation has revealed that a sperm donor carrying a rare, aggressive cancer-causing gene mutation unknowingly fathered at least 197 children across Europe. The sperm was distributed by the European Sperm Bank (ESB), headquartered in Copenhagen, to 67 clinics in at least 14 countries. The mutation, which leads to Li-Fraumeni syndrome, has already resulted in some of the children developing cancer, and some have died at a very early age. The mutation was not detected during initial screening because it was a rare, previously unknown variant that was not part of standard genetic tests at the time of donation. 

The investigation was conducted by 14 public service broadcasters, including the BBC, as part of the European Broadcasting Union's (EBU) Investigative Journalism Network.

The Sperm Donor

The sperm came from an anonymous donor who began donating as a student in 2005 and continued for several years. Over a 17-year period, his sperm was used by multiple women to conceive children. Although he is healthy and passed standard donor screening tests, a mutation had occurred in some of his cells before birth. This mutation affected the TP53 gene, a vital gene that helps protect the body from developing cancer by controlling abnormal cell growth.

While most of his body doesn't carry the mutated TP53 gene, up to 20% of his sperm do. If a child is conceived from one of these affected sperm, the mutation would be present in every cell of that child's body, increasing their risk for certain cancers. The man was identified in November 2023 by the European Sperm Bank, based in Denmark. 

 Li Fraumeni syndrome

This condition is known as Li-Fraumeni syndrome, a rare genetic disorder that significantly increases the risk of developing cancer. It often leads to cancers in childhood, including brain tumors and sarcomas, and breast cancer in adulthood.

To monitor the high cancer risk, individuals with this syndrome require annual full-body and brain MRI scans, along with abdominal ultrasounds, to detect tumors early. Many women with the mutation also choose preventive mastectomies to reduce their cancer risk.

"It is a dreadful diagnosis. It's a very challenging diagnosis to land on a family, there is a lifelong burden of living with that risk, it's clearly devastating," Prof Clare Turnbull, a cancer geneticist at the Institute of Cancer Research in London, told the BBC.

The European Sperm Bank stated that the donor and his family are healthy, and the mutation is not something typically detected by standard genetic screening. Once the issue with his sperm was identified, the bank said the donor was immediately withdrawn from the program.

The Investigation

The ESB was first alerted in 2020 after a child conceived with the donor's sperm was diagnosed with the mutation. However, the bank initially concluded the test was negative and returned the sperm to the market. It was only after a second case in 2023 that the donor was permanently blocked.

Initially, 23 out of 67 children were found to have the TP53 gene variant, with 10 already diagnosed with cancer. Further investigation reveals the donor fathered at least 197 children across Europe, but the exact number is unclear due to incomplete data from some countries. The number of children who inherited the variant is also unknown.

Dr Edwige Kasper, a cancer geneticist at Rouen University Hospital, in France, who presented the initial data, told 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 investigation also found that the donor's sperm was used to produce far more children than the ESB's self-imposed limit of 75 families, and it also exceeded national limits in countries like Belgium and Spain. This has raised concerns about the lack of international regulation and tracking of sperm donors.