Almost one in 10 Britons believe marriage between first cousins should be legal, according to new polling. The figures, published today by YouGov, show that while 9% of adults nationwide think cousin marriage should remain legal, this proportion rises to 39% within the British Pakistani and British Bangladeshi communities.

While marriage between first cousins is currently legal in the UK, in December Conservative MP Richard Holden called for the practice to be banned. Parliament is currently reviewing his proposed legislation, with the bill’s second reading planned for July. Holden has argued that the offspring produced by first-cousin marriages are roughly twice as susceptible to birth defects, and that a ban should be enforced for the sake of public health and women’s freedom.

According to the YouGov figures, over three-quarters of Britons — 77% — think cousin marriage should be made illegal, while 15% say they “don’t know” whether it should be illegal. This disapproval is consistently high among various ethnic groups, including white, black and Indian Britons. While Pakistani/Bangladeshi Britons are considerably less likely to support banning the practice than other groups, this figure is still a plurality (47%) of the total.

Cousin marriage is more common within certain South Asian minority communities in the UK, with roughly half of Pakistani-heritage marriages in Britain estimated to be between cousins. These numbers are far from new: between 2000 and 2010, 39% of British Pakistani couples in the whole of Bradford were first cousins.

Though over three-quarters of voters from each of Britain’s four main political parties think first-cousin marriage should be illegal, one notable detail in the YouGov polling is that younger adults are more supportive of the practice than older generations. Overall, 15% of respondents aged 18-24 think cousin marriage should be legal, compared to 8% of the 25-49 contingent and 7% of those aged 50-64. In December Holden highlighted the risk posed by cousin marriage to young Pakistani women in particular, pointing to a “clan mentality” and “strict honour codes” which limit their choice of partner.

However, Holden’s proposals aren’t universally supported in Parliament. At the end of last year, independent MP Iqbal Mohamed argued that cousin marriage shouldn’t be “stigmatised” and encouraged the use of “advanced genetic test screening” for prospective couples instead. He added that the practice “helps build family bonds […] and puts families on a more secure financial foothold”. Earlier this year, Prime Minister Keir Starmer suggested that he would block any attempt to change the law as it currently stands. Meanwhile, charities that support survivors of forced marriage have criticised Holden’s bill for allegedly creating an “Islamophobic” backlash against communities in which the practice is most prevalent, as well as infringing on personal freedoms.

First-cousin marriage is “not really conducive to modern British society”, Holden said in December. “It’s about more than one marriage. It’s about the values and foundations of our society and our democracy.”