500 children born to just 17 sperm donors

Experts call for enhanced DNA screening amid fears defective genes could pass to dozens of children

Seventeen British sperm donors have fathered more than 500 children between them, figures show.

It has led to fears that men could be unknowingly passing defective DNA to dozens of youngsters, because donors are not screened for faulty genes such as those that can increase the risk of some cancers. It also raises the risk that siblings could meet and form relationships without realising they were related. The Ovarian Cancer Action charity urged authorities to introduce more stringent regulation.

SEVENTEEN British sperm donors have fathered more than 500 children between them, figures show.

It has led to fears that men could be unknowingly passing defective DNA to dozens of youngsters, because donors are not screened for faulty genes such as those which increase the risk of ovarian and breast cancer. It also raises the risk that siblings could unexpectedly meet and form relationships without realising they were related.

Although more than 18,000 children have been born who have at least nine other half-brothers or sisters, just 163 are registered on the Donor Sibling Link, which attempts to reunite them.

Figures from the Human Fertilisation and Embryology Authority (HFEA) showed that 17 men had fathered at least 30 babies each between 1991 and 2015. A further 104 men have fathered between 20 and 29 babies, and 1,557 between 10 and 19. More than 6,000 have created nine or fewer.

Although donated sperm is screened for major diseases such as HIV, hepatitis B and C, Creutzfeldt-jakob disease (CJD), Huntington’s disease and cystic fibrosis, clinics do not yet test for genes which increase the risk of cancers or conditions such as Alzheimer’s disease.

Up to 60 per cent of women who carry the BRCA1 mutation will develop ovarian cancer in their lifetime, compared with just two per cent of the general population, and up to 90 per cent will develop breast cancer.

Ovarian Cancer Action warned that the genetic testing process was only carried out where there is family history of cancer, adding that donor-conceived children can face “enormous barriers” in accessing checks. Marieclaire Platt, the charity’s head of campaigns, said: “Without proper screening for hereditary cancer gene mutations, donors could unknowingly pass on an inherited risk of ovarian, breast, bowel and other cancers.

“We urge the regulators to take action and include hereditary cancer gene mutation screening in the process of sperm and egg donation.”

Under HFEA rules donors are not allowed to create more than 10 families, which means many of the youngsters will live with their half-siblings, and all may end up carrying a defective gene.

Both men and women can pass on the BRCA1/2 gene mutations and there is a 50 per cent chance of a child acquiring it if one parent is a carrier. However, if both are carriers the child

‘Donors could unknowingly pass on an inherited risk of ovarian, breast, bowel and other cancers’

will definitely inherit the mutation.

Geoff Trew, the clinical director of The Fertility Partnership, one of Britain’s largest IVF providers, and a researcher at Imperial College, said he believed enhanced screening would soon be used on UK sperm donors.

“I think over the next year we will start to see clinics bringing in enhanced screening. It could highlight if there was a very big risk of passing on a defective gene,” he said.

However, Prof Allan Pacey, of the University of Sheffield, said further screening could lead to a sperm shortage. Around a third of donated sperm for IVF is imported from abroad.

“There isn’t such a thing as a perfect donor,” he said. “Everyone has a defective something, and if we are going to start screening everything out you may get to a point where we have no sperm donors left at all.”