NHS Withdraws Controversial Guidance on First-Cousin Marriages

In September 2025, NHS England’s Genomics Education Programme published a widely discussed article on consanguineous marriage (marriage between blood relatives), which included both the genetic risks and some potential “social benefits” of such unions, particularly focusing on first-cousin marriages. The article, which was later removed in response to significant public and political backlash, sparked intense debate about the role of the National Health Service (NHS) in guiding social and medical practices. This article examines why the NHS’s guidance on this issue was controversial, the legal and health implications of first-cousin marriage in the UK, and the ongoing debate surrounding proposed legislative changes.

Why the NHS Guidance Was Controversial

The guidance, which appeared on the NHS England website, was intended to inform the public about the genetic risks associated with consanguineous marriages while also mentioning some purported “social advantages.” Among the claims highlighted in the article were the potential for “stronger extended family support systems” and “economic advantages” for those within certain communities.

However, the inclusion of such social benefits—despite the well-documented health risks associated with marrying close blood relatives—immediately drew widespread condemnation from various quarters. Critics, including prominent public health figures, policymakers, and members of the public, argued that the NHS was irresponsibly downplaying serious health risks.

The most significant concern raised by detractors was the suggestion that there might be positive aspects to such marriages, given the strong evidence linking consanguinity to an increased risk of genetic conditions. The inclusion of any benefits was perceived as an attempt to “normalise” a practice that many consider harmful, especially considering the broader societal implications. Calls for an apology from NHS England quickly followed, with critics stating that such guidance could encourage dangerous attitudes towards first-cousin marriages and lead to public confusion.

In response to the controversy, NHS England removed the article from its website and issued a clarification. A spokesperson for the NHS explained that the article was intended to reflect the ongoing debate surrounding consanguineous marriages, rather than to promote an official position. They emphasized that NHS England is committed to providing accurate medical advice and does not endorse any specific stance on the legality or social acceptability of first-cousin marriages.

First-Cousin Marriage in the UK: Legal and Health Considerations

Despite the controversy surrounding NHS guidance, first-cousin marriages remain legal in the UK, a status that has existed for centuries. The legality of such unions dates back to the 16th century, and they are still permissible under British law today.

However, while first-cousin marriages are legally allowed, there are serious genetic risks associated with children born of such unions. Extensive research indicates that the likelihood of birth defects and genetic disorders increases significantly when first cousins marry. The chance of a child being born with a genetic condition is estimated to double from the general population’s 2-3% to a range of 4-6% in cases where the parents are first cousins.

This increased genetic risk is due to the higher probability that both parents will carry recessive genes for certain inherited conditions. When cousins marry, the likelihood of these recessive genes being passed on to offspring is significantly higher, leading to an increased risk of disorders such as cystic fibrosis, sickle cell anaemia, and thalassaemia, among others.

While the risk may seem modest, it is not something to be taken lightly, particularly when it is well established in medical literature. Critics of consanguineous marriages argue that the potential health consequences, both for children and for the broader healthcare system, should be openly discussed in all public health communications.

Ongoing Debate: Should First-Cousin Marriages Be Outlawed?

The debate over the acceptability of first-cousin marriages is not just confined to the pages of medical journals or public health websites—it has become a political issue. In early 2025, Conservative MP Richard Holden introduced a bill to outlaw first-cousin marriages in the UK, citing public health concerns and the genetic risks associated with such unions. Holden’s proposal also touched on broader issues related to freedom, suggesting that the government should take a stronger stance in regulating marriages that could negatively impact children’s health.

Supporters of the bill argue that the state has a duty to protect public health and prevent avoidable genetic disorders. They point to countries like Denmark, where consanguineous marriages are strongly discouraged due to the heightened risk of genetic diseases. In their view, banning first-cousin marriages would be a proactive step in safeguarding future generations.

On the other hand, opponents of the proposed ban argue that it is a misguided move that could stigmatise certain communities, particularly those where consanguineous marriages are more culturally accepted. They believe that education and awareness are better tools to address the risks, rather than blanket legislation that could unfairly target specific groups. There is also the argument that freedom of choice, especially in private matters such as marriage, should not be infringed upon by the state.

Without significant government backing, Holden’s bill faces an uphill battle in Parliament. However, the fact that such a proposal is being debated signals that the issue of first-cousin marriage will likely continue to be a topic of discussion for years to come.

NHS’s Official Stance: No Policy, Just Information

Following the storm of controversy, NHS England’s spokesperson clarified that the article on consanguineous marriage did not reflect an official NHS stance on the practice. The purpose of the article was to provide a balanced summary of the existing debate, touching on both the genetic risks and the social arguments put forward by proponents of consanguineous unions.

The spokesperson reiterated that NHS England recognises the serious genetic risks associated with first-cousin marriages and emphasised that any advice given to patients on this issue would focus on providing factual information and medical guidance, not on dictating personal or cultural choices.

While the NHS does not take an official position on the matter of first-cousin marriages, it remains committed to providing high-quality, evidence-based information to help individuals make informed decisions about their health.

The Political Dimension: A Shift in Social Norms?

The NHS’s initial guidance, which highlighted not only the health risks but also the purported “social benefits” of first-cousin marriages, has been seen by some as a reflection of a broader trend within certain political circles to downplay or soften concerns about cultural practices that diverge from mainstream British norms. The suggestion that first-cousin marriages could offer “stronger extended family support systems” and “economic advantages” raised eyebrows, particularly among those who see the potential medical risks as outweighing any social benefits.

This kind of thinking, which some critics argue amounts to a political stance, seems to align with broader trends seen within the political left. In recent years, left-wing political ideologies in the UK have increasingly embraced a more relativistic approach to cultural and social norms. In this context, support for first-cousin marriages may be viewed as part of an effort to accommodate and validate diverse cultural practices, particularly those within communities where such unions are more common. Critics argue that this approach risks prioritising cultural sensitivity over the potential health risks to future generations, bending to the will of cultural advocacy groups rather than sticking to the principles of public health and scientific evidence.

While some argue that acknowledging cultural practices is vital in fostering inclusivity (including unprecedented numbers of immigrants from nations where this is commonplace), others see it as a potential compromise on public health that could be influenced by political correctness or an overly cautious approach to cultural engagement. In this light, the NHS’s guidance has come to symbolise the tensions between medical objectivity and the political pressures to be more accommodating of diverse, and sometimes controversial, practices.

The NHS’s controversial guidance on first-cousin marriages has ignited a broader conversation about the role of public health institutions in addressing cultural practices that may pose risks to individual and public health. While first-cousin marriages remain legal in the UK, they carry significant genetic risks, which cannot be overlooked. The controversy surrounding the NHS’s guidance highlights the need for clear, responsible communication from health authorities on such sensitive topics. As the debate continues, it is clear that the public, medical professionals, and policymakers will need to engage in thoughtful discussion to ensure that future decisions strike the right balance between protecting public health and respecting individual freedoms.