Statistics show first-cousin marriages roughly doubles the risk of congenital defects and genetic disorders in children.
Statistics show it roughly doubles the risk of congenital defects and genetic disorders in children (Image: Getty Images)
Hospital bosses have been told to stop discouraging first-cousin marriages despite an increased risk of birth defects.
Guidance has been issued because the risk of giving birth to a baby with a genetic disorder is only “slightly increased” for closest extended family members having children.
The National Child Mortality Database (NCMD), which holds information on all children who die in England, has told NHS staff “it is unacceptable to discourage close-relative marriage in a blanket way” because parents are only at a “slightly increased” risk of having a child with a genetic disorder. It said genetic counsellors should meet the couple and their relatives to advise them on how to “consider arranging future marriages outside of the family”.
Richard Holden, the Conservative MP who is campaigning to ban cousin marriage, said: “Our NHS should stop taking the knee to damaging and oppressive cultural practices. This guidance turns basic public health into public harm.”
Mr Holden said ignoring the health risks “helps no one, least of all the children born with avoidable conditions and those trapped in heavy-handed patriarchal power structures they can’t leave for fear of total ostracism”.
Warning: Mr Holden is campaigning against first-cousin marriage (Image: Jonathan Buckmaster)
First-cousin marriage, which is common in the British-Pakistani community, remains legal despite warnings it raises the risk of children ending up with birth defects.
Statistics show it roughly doubles the risk of congenital defects and genetic disorders in children, rising from a baseline of 2–3% in the general population to approximately 4–6%.
The primary cause is an increased likelihood of inheriting autosomal recessive disorders where both parents carry the same mutated gene.
Commonly associated birth defects and genetic disorders include infantile cerebral palsy, hearing loss, and visual disabilities and musculoskeletal issues like muscular dystrophy.
The proposed Marriage (Prohibited Degrees of Relationship) Bill seeks to add first-cousin marriages to the list of prohibited relationships in England and Wales, which currently only includes direct siblings, parents, and children.
The NCMD, based at the University of Bristol, has received more than £3.5 million in taxpayer funding to record and interpret data on all children who die. The document was first issued in 2023.
Ministers have faced mounting calls to ban cousin marriage in recent years because of potential health problems for the children of blood relatives.
Michael Muthukrishna, professor of economic psychology at the London School of Economics, said: “When marriage is restricted to family members, communities become more isolated, limiting social integration. This isolation is what has allowed for over-representation of radicalisation and grooming gangs.”
Independent MP Iqbal Mohamed said education programmes to raise awareness of the risks would be more effective than a ban.
Downing Street said expert advice on the risks of first-cousin marriage was clear but indicated the Government had no plans to change the law.
The NCMD said its purpose was to collect data on deaths and share its findings and that it did not instruct the NHS or its staff on practice except on data collection and when it “makes recommendations for professionals to help reduce mortality in children”.
An NHS spokesperson said: “This is not official NHS guidance.
“The evidence is clear that having closely related parents increases the risk of inherited genetic conditions and serious illness, and while cases like this exist, the NHS must ensure support is in place for children at risk.”
