The official midwifery guidance, used in NHS England training, reportedly described concerns about congenital diseases as “exaggerated” and “unwarranted”, claiming that 85 to 90 per cent of cousin couples do not have affected children. By contrast, around 98 per cent of children in the general population are born without congenital conditions.
While the document acknowledged that there are “risks to child health associated with close relative marriage”, it stated these should be “balanced against the potential benefits”.
The guidance suggested that marriage between relatives could bring “economic benefits”, alongside emotional, social and kinship ties, and warned healthcare professionals not to stigmatise patients particularly those from south Asian or Muslim backgrounds where cousin marriage is considered culturally normal.
The revelations prompted a swift backlash from senior politicians and medical commentators.
Stuart Andrew, the shadow health secretary, described the guidance as “absolutely bonkers”, adding: “This has no place in our NHS. Midwives should be focused on protecting women and babies, not normalising practices that carry well-documented risks. Cousin marriage is not safe, and healthcare professionals should never be encouraged to downplay those dangers.”
NHS England confirmed it began investigating on Sunday after the document was released publicly following a freedom of information request. Officials said any “inappropriate wording” would be removed.
First cousin marriage remains legal in the UK and is relatively common within some communities, particularly among people of Pakistani heritage. However, scrutiny of its health implications has intensified in recent years, with research consistently showing a higher likelihood of genetic disorders among children born to closely related parents.
The guidance formed part of NHS England’s Maternity Transformation Programme, which aims to halve stillbirths, neonatal and maternal deaths, and brain injuries by 2030.
One training document reportedly stated that discouraging cousin marriage would be “alienating and ineffective”, arguing that the increased risk of genetic conditions had “often been exaggerated”, leading families to feel “shamed and blamed”.
Richard Holden, the Conservative MP campaigning for a ban on cousin marriage, said he found the guidance “unbelievable”, warning that there were “no benefits” to first cousin marriage and “massive downsides for health, welfare, individual rights and social cohesion”.
Michael Muthukrishna, professor of economic psychology at the London School of Economics, also criticised the approach, arguing that restricting marriage to family members increases isolation within communities. He warned that such isolation can contribute to wider social harms, while failing to protect mothers or babies from well-established genetic risks.
Concerns have been heightened by previous figures showing that more than two child deaths a week in England were linked to parents being closely related. Data also revealed that up to 20 per cent of children treated for congenital disorders in cities such as Birmingham and Glasgow were of Pakistani descent, compared with around 4 per cent in the wider population.
In a statement, the NHS said it fully recognises the genetic risks of consanguineous relationships and offers referrals to genetics services so families can make informed decisions.
“We are investigating whether this inappropriate wording appears in any guidance or training materials, and we will take steps to remove it,” an NHS spokesperson said.
The Department of Health and Social Care added: “The medical evidence is clear. First cousin marriages are high risk and unsafe, and we know the harm genetic defects can cause. We are working with the NHS to understand how this guidance was developed and to ensure it does not happen again.”
