A donor who unknowingly carried a gene mutation that sharply increases cancer risk has fathered nearly 200 children across Europe, an extensive investigative report shows.
The mutation alters cancer-suppressing processes in the body. Although the donor’s own health appeared normal at screening, some of his sperm carried a faulty version of a key gene, TP53. As a result, roughly up to one in five of his sperm contained this dangerous variant, while the rest did not. Any child conceived with the affected sperm would carry the mutation in every cell of their body, creating Li–Fraumeni syndrome, which can drive a very high lifetime cancer risk—up to about 90%, with cancers often appearing in childhood or later as breast cancer in adulthood.
This donor’s sperm was not sold to UK clinics, but a small number of British families did use it during fertility treatments in Denmark, according to the BBC. Denmark’s European Sperm Bank acknowledged this and expressed sympathy for those affected, noting that the donor’s mutation could not be detected by routine preventative genetic screening and that, once the issue came to light, the donor’s samples were blocked from further use.
The investigation, a collaboration among 14 public-service broadcasters under the European Broadcasting Union’s Investigative Journalism Network, reveals that the donor began donating in 2005 and, over about 17 years, his sperm was used by clinics in multiple countries.
The donor’s sperm was distributed to 67 fertility clinics across 14 nations. While the UK did not receive his sperm, authorities later informed the UK’s HFEA that some British patients had traveled to Denmark for treatment using this donor’s sperm, and those individuals have since been contacted.
Clinicians who treated children with cancer linked to donor sperm raised concerns at the European Society of Human Genetics, noting cancer diagnoses among affected children and reporting more cases than previously disclosed. Freedom-of-information requests and interviews indicate the true number of children fathered by this donor is at least 197, with the possibility that the figure will rise as additional data become available from other countries. Some children have already developed cancer, and a number have faced multiple cancers or early fatalities.
One French mother, Céline (a pseudonym), learned that her child—conceived with this donor’s sperm 14 years ago—carries the mutation. She recalls being told to have her daughter screened and emphasizes that while she does not blame the donor personally, it was unacceptable to use sperm that carried a known risk. She faces the ongoing reality that cancer could emerge at any time for her child and possibly for other relatives.
In total, the donor’s sperm was used by 14 countries and 67 clinics. Although the Danish clinic involved in these cases notified the UK’s authorities, it remains unclear how many British patients in other settings were affected. Parents who may be impacted are encouraged to contact their clinics and local fertility authorities.
Experts note that there is no global cap on the number of families a sperm donor can serve, but individual countries set their own limits. In Belgium, for instance, a single donor’s sperm was intended for up to six families but ended up used by 38 women, yielding 53 children. The UK imposes a 10-family limit per donor.
Some specialists argue that a stricter cap could reduce the risk of spreading rare hereditary conditions and lower social complexities from hundreds of half-siblings sharing the same donor. The European Society of Human Reproduction and Embryology has proposed a cap around 50 families per donor, though they caution this would not eliminate all genetic risk and would not automatically solve the broader social and psychological implications.
The European Sperm Bank contends that the vast majority of pregnancies achieved with donor sperm are safe and that donors are screened according to medical guidelines. They also stress that thousands of intended parents rely on donor sperm to have children.
If you’re considering donor sperm, experts recommend using a licensed clinic that conducts comprehensive screening for genetic and other health concerns. When evaluating donors, it can be sensible to ask about how many times a donor’s samples have been used and whether a donor’s contributions have previously resulted in affected offspring.
If you or someone you know has been affected by issues raised in this story, you can find support resources at BBC Action Line. Would you share your views on whether stricter donor-use limits are the right path, and how best to balance safety with access to family-building options?
