Sperm donor with rare genetic mutation fathered 67 children. Ten now have cancer, prompting calls for reform

CNN

27-05-2025

The sperm of a man carrying a rare genetic mutation linked to cancer was used to conceive scores of children across Europe, prompting calls for greater regulation and a limit on the number of births allowed from a single donor.
Sperm from the donor was used to conceive at least 67 children from 46 families born between 2008 and 2015, said Edwige Kasper, a biologist at Rouen University Hospital in France, during a presentation at the annual conference of the European Society of Human Genetics in Milan on Saturday. Ten of the children have already been diagnosed with cancer.
'At the heart of the problem seems to lie the regulation, or maybe the lack of regulation, of the number of births by a single donor,' she said.
Analysis showed that the donor, who is himself healthy, had a rare mutation in a gene named TP53, which is likely to cause Li-Fraumeni syndrome, a rare disorder that increases a person's risk of developing cancer.
The mutation was not known when the donation was made, but children born from this donor have since been identified in eight different European countries: Belgium, Denmark, France, Germany, Greece, Spain, Sweden and the United Kingdom, said Kasper in her presentation.
Ten of them have been diagnosed with cancers such as brain tumors and Hodgkin lymphoma, and another 13 children are carrying the gene but have not yet developed a cancer.
They will require regular medical examinations due to their increased risk of developing cancer, and have a 50% chance of transmitting it on to their own children, said Kasper.
'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,' said Kasper in a press release.
Unlike in some cases of serial sperm donors, such as a Dutch man who was ordered to stop donating sperm after being found to have fathered between 500 and 600 children around the world, this man only donated to a single private sperm bank in Denmark named the European Sperm Bank.
Julie Paulli Budtz, vice-president of corporate communications at the European Sperm Bank, told CNN that it was 'deeply affected by this case.'
'The donor has been thoroughly tested even above the required standards, but preventative genetic screening is reaching its limits here,' she said in a statement sent to CNN on Monday.
'Every human being has about 20,000 genes, and 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.'
There is currently no limit on the number of children that are allowed to be born using a single donor, something which Budtz said the European Sperm Bank would like to change.
'This is also why, in addition to following national pregnancy limits, we have proactively implemented our own international limit of 75 families per donor,' she said.
This limit is self-imposed as regulations vary from country to country. For example, France has a limit of 10 births per donor, while Denmark allows 12 and Germany allows up to 15, according to the press release.
'There is a major issue here concerning a lack of harmonised regulation across Europe,' Kasper said 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.'