Overview
- Samples from the Denmark-based European Sperm Bank were used over roughly 17 years at 67 clinics, with up to 20% of the donor’s sperm carrying the TP53 variant linked to Li‑Fraumeni syndrome.
- Children who inherit the variant face an estimated 90% lifetime cancer risk, and clinicians report multiple diagnoses in affected children with some deaths already confirmed.
- The UK regulator said no licensed UK clinics received the sperm, but a very small number of British women treated in Denmark were notified by those clinics.
- The European Sperm Bank said the mosaic mutation is not detected by standard preventive genetic screening and confirmed the donor was blocked in 2023 once identified.
- National limits were exceeded in some countries, including Belgium where 38 women had 53 children despite a six‑family cap, fueling calls for tighter screening, donor‑use limits and international coordination.