The social construction of genetic risk

Richard Holden MPs’ unsuccessful Private Members Bill to ban cousin marriage provoked a debate in the UK Parliament and in the media in 2024/5. It was a debate that conflated a genetic risk with a social practice. The risk being addressed was the transmission of recessive genetic disorders from parent to child. The social practice was marriage between cousins.

The notion of risk is a complex one. Every European carries, on average, two gene defects that can lead to recessive disorders but for these to impact a child both parents need to have the same one. First cousins share one eighth of their genes, this increases the chance – one in sixteen children born to first cousins will have a recessive disorder. The complexity then is that recessive disorders occur randomly, in cousins their occurrence increases but fifteen out of sixteen children born to first cousins will not have a disorder. Further, some people are genetically similar to first cousins even if they are not knowingly related. If marriages take place over generations within restricted population groups – perhaps in rural or island communities, within ethnic or religious groups, in groups intent on preserving their own social status and wealth (the aristocracy and royal families have done this, as have clans, castes and biraderi) – then the genetic pool from which marriage partners are drawn is far from random and risk of recessive disorders increases.

In the UK the group that excites most concerns about enhanced genetic risk is Muslims of Pakistani heritage. This is a group that has favoured cousin marriage in their country of origin and in their various diasporas. They are also a group which has been vilified for this practice.

Changing the law and changing minds

It is too simplistic to conclude that if one passes a law stopping cousins from marrying it will reduce genetic risk to children. Making marriage between cousins illegal will only stop state-sanctioned marriage. It does not consider how marriage as a legal and social practice can be separated. In the UK, virtually all Pakistani heritage Muslims have an Islamic faith marriage, a Nikah. Not everyone has a civil marriage. In 2020, the Court of Appeal ruled that Nikahs are not valid under UK law. A ban on marriage is likely to further reduce civil ceremonies and with them the protection that the law provides, including protection for children should marriages break down. Invoking the law without considering the causes of the practices being targeted, or without taking cognisance of the options people have available, is unlikely to be effective.

There are alternative ways of reducing the risk of recessive disorders. The sequencing of the whole genome is becoming more widespread (and cheaper). Couple sequencing is possible and could be offered to those who are considered, or who consider themselves, at high risk. We have expert genetic counsellors and locally based genetic testing – we need more. We have health promotion, health education and primary care services who, with support and encouragement, could foster genetic literacy and so enhance informed choice. But these routes require public engagement and this is less likely in groups who feel themselves marginalised by a public discourse that takes a community practice and loads onto it a series of toxic tropes.

Those promoting the private members bill argued that their intention was to improve child health. But this intention accrued others, specifically enhancing social cohesion and preventing a practice that, it was argued, was not consistent with “our values”. It was a manifestation of “medieval views” and as such was alien to the “prevailing culture”. Further, it was perpetuating a division between Pakistani heritage communities and “the rest of us”. Any attempt to base the debate on data was pushed aside by the uncomfortable experience of hearing people assume their values are our values and that the prevailing culture is their culture.

The debate then gathered auxiliary motivations: a ban would help discourage forced marriage and protect women from domestic violence; links were made to the Rochdale and Rotherham sex-trafficking scandals; to children being coerced into marriage; to an honour violence culture; to reports of father-daughter and sibling incest and to claims that cousin-marriage strongly correlated with corruption and poverty. A starting point that was about a concern with child health became a vector for piling on prejudicial assertions that were floating around the grimy reaches of our popular discourse. Stigmatisation via stoking moral panic is not going to encourage the sort of take-up of health services that would make a real difference to child health.

The biological and the social

For recessive disorders, a genetic risk increases when it is enacted via a particular configuration of partner choice that has been a key part of the social identity of a particular group. The espoused intent of that choice has been to preserve family land and wealth and foster family and community solidarities, thus mitigating vulnerabilities in insecure environments. An adjunct consequence, generated outside the group, is stigmatisation. Both the interface of biological determinism mediated by complex constellations of risk, and identity-making via partner choice and via others’ reaction to it, provides many entry points for sociologists to explore and critique.

Legislate or educate about risk?

Many of the claims made for how understanding our genes can improve health are framed as being about “personalised medicine”. But genetic risk is shaped by social structures and by our choices and the behaviour of others.

If we look to the law to provide solutions to health problems but ignore the social dimensions that underpin the behaviours we think we are targeting, we risk unintended consequences.  If we look to the law to define what is allowed in our intimate lives, we must be open about the moral assumptions we are making and about the prejudices we have.