Cousin marriage: What new evidence tells us about children's ill health

In a bustling home in Bradford, three sisters are excitedly preparing for a family wedding. The atmosphere is filled with joy as a beautician styles their hair and makeup, creating a scene reminiscent of a charming storybook. The sisters, all in their late 20s, engage in lively conversations about marriage, especially since the upcoming wedding is between two first cousins. While some may find this practice unusual, it is quite common in their family and in certain areas of Bradford. Ayesha, the eldest sister at 29, married her first cousin in 2017 and has two children with him. She describes their marriage as perfectly normal, as their mother, a Pakistani immigrant, expected all her daughters to follow the same path. In contrast, the youngest sister, 26-year-old Salina, chose to break tradition by having what is known as a 'love' marriage, selecting a partner from outside the family. Salina, who is outgoing and ambitious, felt that marrying a cousin did not appeal to her. The middle sister, Mallika, who is 27, remains single and has already decided against marrying within the family. She believes that her education has opened up many opportunities for her, and she notes that the mindset around marriage has shifted significantly over time. In the UK and across Europe, cousin marriage is facing increased scrutiny, particularly from the medical community, which raises concerns about the health of children born to first cousins. Recent research from Bradford has added to these worries. Researchers at the local university have been conducting a long-term study, now in its 18th year, which began between 2007 and 2010. They recruited over 13,000 babies in the city and have been closely following their development from childhood into adolescence and now into early adulthood. A significant portion of the children in the study have parents who are first cousins, primarily from Bradford's Pakistani community, making this research one of the most valuable studies on the health impacts of cousin marriage. Recent findings indicate that children of first cousins may face more health issues than previously understood. The researchers examined various aspects of the children's health, including their speech and language development, frequency of healthcare visits, and academic performance. They aimed to isolate the effects of having related parents, even after accounting for factors like poverty and parental education. The results revealed that children of first cousins had an 11% probability of being diagnosed with speech and language problems, compared to 7% for children whose parents are not related. Additionally, only 54% of children of first cousins reached a 'good stage of development' by age five, compared to 64% for those whose parents are not related. The study also found that children of first cousins had a higher number of visits to the doctor, averaging four appointments per year, compared to three for children whose parents are not related. Notably, even when considering children with diagnosed recessive disorders, the data suggested that being related might still impact the health of children without any identifiable issues. Neil Small, an emeritus professor at the University of Bradford and the study's author, expressed excitement about the findings, as they provide an opportunity for more accurate responses and targeted interventions to improve health outcomes. While this study is just one piece of research and may not represent the entire UK, it contributes to a growing concern among scientists that has caught the attention of lawmakers across Europe. Some Scandinavian countries have moved to ban cousin marriage entirely. In Norway, the practice became illegal last year, and Sweden plans to implement a ban next year. In the UK, a member of parliament has proposed a private members' bill to outlaw cousin marriage, adding it to the list of illegal unions, which already includes marriages between parents and children, siblings, and grandparents. However, the Labour government has stated that there are currently no plans to impose such a ban. Presently, the UK follows a policy of genetic counseling, where first cousin couples are educated about the risks of having children and encouraged to seek additional screenings during pregnancy. Amid concerns about child health and the strain on the National Health Service, some academics are advocating for a more robust approach to counseling, with increased funding and focused interventions. There are also voices calling for a complete ban on cousin marriage, following the example set by Scandinavian countries. For many in the UK, the idea of marrying a cousin is largely unfamiliar. However, it was not always considered unusual. Historical figures such as Charles Darwin and Queen Victoria married their first cousins. In the 19th century, cousin marriages accounted for nearly one in 20 aristocratic unions in Britain. By the 20th century, the proportion of cousin marriages had declined to about 1%. In Bradford, nearly half of the mothers from the Pakistani community are married to a first or second cousin, according to recent data. Those advocating for a ban often cite the higher risk of birth defects and health issues for children born to cousin parents. Richard Holden, who proposed the bill, highlighted the increased rates of infant mortality and health problems associated with cousin marriages. Some researchers argue that banning cousin marriage could lead to immediate health improvements, particularly in communities where the practice is prevalent. However, others contend that the primary issue may not solely be cousin marriage but also endogamy, where individuals marry within their close community. This can lead to similar genetic risks, regardless of whether the couple are cousins. Education about genetic risks is viewed as a more effective approach than outright bans. In Bradford, there have been ongoing efforts to raise awareness about genetic risks within the Pakistani community, and many families are beginning to change their perspectives on cousin marriage. The sisters we spoke to expressed that attitudes are gradually shifting, partly due to increased awareness of health risks. They believe that education and exposure to different cultures are contributing to this change. Ayesha, who is in a cousin marriage, believes that her children are unlikely to marry their cousins. The practice of cousin marriage is declining in Bradford, with the percentage of new mothers who are first cousins with the father of their baby decreasing from 39% in the late 2000s to 27% in the late 2010s. This decline is attributed to the growing awareness of health risks and the importance of education. While some individuals advocate for a ban on cousin marriage for health and social reasons, others argue that education and support are the most effective ways to address the issue.