Investigation launched after NHS guidance suggested ‘potential benefit’ of marriage between cousins

The NHS is investigating after midwives were reportedly given official training materials suggesting there may be “potential benefits” to marriage between first cousins and claiming “the associated genetic risks [to children] have been exaggerated”.

The emergence of the guidance document, which was released publicly following an FOI request, has prompted alarm due to the increased risk of genetic disorders among children born to consanguineous (related) parents.

In the UK, a child of two first cousins carries a 6 per cent chance of inheriting a recessive disorder, compared to 3 per cent for the general population. Meanwhile, recent research examining the impacts on children of consanguineous parents suggests that, as well as diagnosable genetic disorders, the children of first cousins more frequently experience developmental issues and other health concerns.

Despite this evidence, the NHS training document noted that “85 to 90 per cent of cousin couples do not have affected children”, and said “close relative marriage is often stigmatised in England”.

The guidance also suggests that “any discussion of the potential risks” to a child of first cousins’ health “must also be balanced against the potential benefits” that come from the “collective social capital” of such a relationship.

It also suggested that marriage between first cousins could provide “financial and social security at the individual, family and wider kinship levels”, and added that there had been an “unwarranted, narrow focus on close relative marriage”.

Richard Holden, the Conservative MP for Basildon and Billericay, who is campaigning to ban consanguineous marriage, told The Times: “I just find this unbelievable. It is really concerning to me. There are no benefits to marriage between first cousins, only massive downsides for health, welfare, individual rights and the cohesiveness of our society.”

Marriage between first cousins, which is relatively common in Pakistani and Bangladeshi families in Britain, as well as in other parts of the world, is legal in the UK, despite concerns about impacts on children and potential coercion of women.

A paper published by the Oxford Journal of Law and Religion in 2024 estimated that cousins accounted for 40-60 per cent of all marriages in these communities in the UK, and about 20-40 per cent of marriages in the Irish traveller community. This compares to fewer than 1 per cent of the rest of the population.

Concerns about the practice have fuelled calls to outlaw consanguineous marriage in Britain. In addition to the potential impacts on children, it has been argued that a ban could also halt many forced marriages.

This is not the first time the NHS has suggested there are benefits to marriage between first cousins. In September last year, Health Secretary Wes Streeting led calls for an apology from the health service after an article on NHS England’s Genomics Education Programme said first-cousin marriage was linked to “stronger extended family support systems and economic advantages”.

The midwifery guidance was reportedly produced as part of NHS England’s Maternity Transformation Programme, which aims to halve the number of stillbirths, neonatal and maternal deaths and brain injuries, by 2030.

The NHS has now distanced itself from the document. A spokesperson told The Independent: “The NHS absolutely recognises the genetic risks of consanguineous relationships, and where people consider entering into them, we offer referral to genetics services so individuals understand the risks and can make informed decisions.

“We are investigating if this inappropriate wording is in any guidance or training, and if so, we will take steps to remove it.”

The government has said it is working with the health service to look into how the guidance came to be written to ensure “it doesn’t happen again”.

A Department of Health and Social Care spokesperson told The Independent: "The medical science and evidence is clear. First cousin marriages are high risk and unsafe, and we know the genetic defects and harm they can cause.

“We are working with the NHS to look into how this guidance was developed, and to make sure it doesn’t happen again.”