Sperm Donor with Cancer Gene Fathers 197 Children, Spurring Reform

A sperm donor who carried a genetic mutation dramatically increasing the risk of Li-Fraumeni syndrome (LFS), a cancer predisposition syndrome, has fathered at least 197 children across Europe. The donor's sperm was sold by Denmark's European Sperm Bank over a period of about 17 years starting in 2005.

Children Affected: At least 197 children were conceived using the donor's sperm across 67 fertility clinics in 14 countries. Genetic Risk: The donor unknowingly harbored a mutation in the TP53 gene in up to 20% of his sperm. Children who inherited this mutation face an up to 90% chance of developing cancer, consistent with LFS.

Confirmed Cases: Initial data presented at the European Society of Human Genetics found 23 children with the variant out of 67 children known at the time. Ten of those had already been diagnosed with cancer, and some have died at a very early age.

Breach of Limits: The European Sperm Bank admitted that country-specific usage limits were breached in some cases. For example, in Belgium, where the limit is six families per donor, this donor fathered 53 children from 38 different women.

UK Involvement: A "very small" number of British families used the donor's sperm while receiving treatment in Denmark and have been informed. The sperm was not sold to UK clinics.

The European Sperm Bank stated the donor passed initial screening and that such a rare mutation is "not detected preventatively by genetic screening".