Sperm from donor with cancer-causing gene was used to conceive almost 200 children

A sperm donor who unknowingly harboured a genetic mutation that dramatically raises the risk of cancer has fathered at least 197 children across Europe, a major investigation has revealed.

Some children have already died and only a minority who inherit the mutation will escape cancer in their lifetimes.

The sperm was not sold to UK clinics, but the BBC can confirm a "very small" number of British families, who have been informed, used the donor's sperm while having fertility treatment in Denmark.

Denmark's European Sperm Bank, which sold the sperm, said families affected had their "deepest sympathy" and admitted the sperm was used to make too many babies in some countries.