A major study has found that a sperm donor who unknowingly contained a genetic mutation that dramatically increases the risk of cancer has fathered at least 197 children across Europe.
The research was carried out by fourteen public broadcasters, including the BBC, as part of the European Broadcasting Union’s Investigative Journalism Network.
Some children have already died and only a minority who inherit the mutation could avoid cancer during their lifetime.
Even though the semen was not sold in British clinics, BBC reported that a “very small” number of British families, who have been notified, have used donor sperm during fertility treatment in Denmark.
Denmark’s European Sperm Bank, which sold the sperm, said it had its “deepest sympathy” with the affected families and admitted the sperm was being used to make too many babies in some countries.
The sperm, which has been used for almost fifteen years, comes from an anonymous man who was paid to donate as a student starting in 2005.
He was a healthy individual and passed donor screening checks, but the DNA in some of his cells mutated before he was born.
It damaged the TP53 gene – which plays the crucial role of preventing the body’s cells from becoming carcinogenic.
Most of the donor’s body does not contain the dangerous form of TP53, but up to 20% of his sperm does.
However, all children created from affected sperm will have the mutation in every cell of their body.
This is known as Li Fraumeni syndrome and carries an up to 90% chance of developing cancer, especially during childhood and breast cancer later in life.
Professor Clare Turnbull, a cancer geneticist at the Institute of Cancer Research in London, spoke to the BBC and said: “It’s a terrible diagnosis. It’s a very challenging diagnosis to land on a family, living with that risk carries a lifelong burden, it’s clearly devastating.”
Meanwhile, the European Sperm Bank said that the “donor himself and his relatives are not sick” and that such a mutation “is not preventively detected by genetic screening.” They also assured that they “immediately blocked” the donor as soon as the problem with his sperm was discovered.
