A Danish sperm donor, who was unknowingly a carrier of a genetic mutation that dramatically increases the risk of cancer and has “fathered” at least 197 children across Europe—including in Greece—has been revealed through investigative journalism by 14 organizations.

According to the investigation, seven clinics in Greece received sperm from this Danish donor. However, authorities did not respond to requests for information, citing legal confidentiality issues.

It became known that in November 2020, a Greek pediatric oncologist identified the TP53 mutation in three children from the same family, conceived via IVF at Greek clinics using sperm from this donor. One of these children has cancer. In 2023, the doctor met a fourth child from the same donor who also carries the mutation.

The European Sperm Bank of Denmark, which sold the sperm, expressed its “deep sympathy” to the affected families and admitted that the sperm was used to conceive many babies in certain countries, as shown in the BBC map.

The sperm came from an anonymous man who was paid to become a donor as a student starting in 2005 and was subsequently used by women for about 17 years. He had passed donor screening, but some of his DNA was mutated before his birth.

“This caused a defect in the TP53 gene, which plays a critical role in preventing the body’s cells from becoming cancerous. Most of the donor’s body does not carry the dangerous form of TP53, but up to 20% of his sperm does. Children conceived from the affected sperm will have the mutation in every cell of their body. This is known as Li-Fraumeni syndrome and is associated with up to a 90% chance of developing cancer, particularly during childhood, as well as breast cancer later in life,” reported the BBC.

“It is a terrible diagnosis. It is very difficult for a family; there is a lifelong burden to living with this risk,” commented Claire Turnbull, a cancer geneticist at the London Institute of Cancer Research.

The European Sperm Bank stated that “the donor himself and his family members are not ill” and that such a mutation “cannot be detected preventively by genetic screening,” adding that the donor was immediately excluded once the problem with his sperm was discovered.

Children have died

The case began to emerge when doctors examining children with cancer linked to sperm donation raised concerns with the European Society of Human Genetics.

They reported identifying 23 children with the mutation out of 67 known at that time, with ten already diagnosed with cancer.

“The investigation revealed that the total number is at least 197 children, though this may not be final as data from all countries is not available. It is also not known how many of these children inherited the dangerous variant,” reported the BBC.

“We have many children who have already developed cancer. Some children have developed two different cancers, and some have already died at a very young age,” said Edwin Kasper, a cancer geneticist at Rouen University Hospital, who presented the initial data.