The cousin marriage debate
Tim Dieppe is Head of Public Policy at Christian Concern. He sat down with me to unpack the arguments around cousin marriage from a recent article he wrote and why this matters for marriage as a public institution. You can listen to Tim explain his arguments fully in our discusion here:
This debate has been back in the news. NHS England has faced scrutiny over training materials that reportedly spoke of “potential benefits” of first-cousin marriage, and suggested genetic risks had been “exaggerated”.
Tim’s argument begins with a simple premise about what marriage is: “I think marriage is meant to be a public institution endorsed by the state and protected by law”. That is why he argues the cousin marriage question cannot be shrugged off as a technicality.
He presses a practical point that is often missed: “Let’s ensure that [all] marriages are registered.” Registration is the gateway to legal protection, particularly for women, when relationships break down. C4M has written about this previously.
A wider theme in the discussion is kinship and coercion. Dieppe argues that restricting close-kin marriage historically helped loosen the grip of coercive clan structures: “The effect of this was to effectively undermine the clan system whereby people are very loyal to their clan”. In that reading, the issue is not only health risk. It is also about freedom and the shape of civic life, he explains.
Tim also tackles a common Christian objection head on: “People say the Bible doesn’t prohibit cousin marriage, therefore we shouldn’t”. His response is that public policy has to deal with modern safeguarding, women’s legal protections, and the reality of coercion.
This subject matters because marriage remains the dominant family form, not a niche choice. The Office for National Statistics estimates that married couple families were still the most common family type in the UK in 2024, making up 65.1% of all families.
Coalition for Marriage supporters come from all faiths and none, and from across the political spectrum. Our common purpose is simple: to champion the original definition of marriage as the union of one man and one woman, and to do so calmly and lawfully, drawing on evidence about family stability and child wellbeing.