Cousin marriages and inbreeding among Pakistanis and Jews in Britain

Marriages between close relatives are seldom a good idea. If such a custom is maintained over a long period of time, the results can be undesirable in the extreme.

As readers are perhaps aware, moves are afoot to make illegal the marriage of first cousins in this country. This move is prompted by the unfortunate outcomes likely if this practice becomes too prevalent in a community. Cousin marriages are a terrible idea and although legal in Britain are the object of a popular taboo as steering closer than is comfortable to incest. Very few marriages in Britain between white people who are not Jews are between cousins; roughly one in 25,000.

The chief reason that cousin marriages are undesirable is that they hugely increase the chance of any offspring being sickly, dying young or suffering from some genetic defect or other. One remembers the royal families of Europe who were, in the past, very fond of this practice. The Habsburgs notoriously preferred to marry into their own line and this led not only to distinctive physical characteristics such as the so-called ‘Habsburg jaw’, but also a powerful strain of mental deficiency. Charles II of Spain was a classic example of this tendency, being unable to speak until he was four, due to a very large tongue and of course an extreme form of the Habsburg jaw. He did not walk until he was eight and always had trouble, even as an adult, in talking. His mother and father were uncle and niece and the complicated family connections meant that his father was also his uncle and Charles was his mother’s cousin, as well as her son. His grandmother was also his aunt (1).

The British royal family too fell victim to the perils of inbreeding within a small group. When one person is a carrier of a defective gene such as that for sickle cell or haemophilia, then there is a risk not only of passing this onto children, but if such a person has children with a person who shares the trait, then the full-blown syndrome may result in their offspring. Of course, if you and your relatives have for centuries been marrying each other, then traits such as haemophilia may become more common than in the general population. Queen Victoria carried the gene for haemophilia and married her cousin Albert, who was also a carrier of the gene. This led to one of their children, Leopold being born with the disease itself. He died from a haemorrhage after a fall. Because Victoria’s children married into the other European royal families, the disease showed up in the Russian and Spanish royal families too; most famously with the son of Tsar Nicholas who died in the aftermath of the Russian Revolution.

In the modern world, Ashkenazi Jews provide a good example of how genetic disorders may be perpetuated in an ethnic group which tends to avoid mating with outsiders. Ashkenazis, who make up 80 % of the world’s Jews, lived for centuries in closed communities in Eastern Europe: marrying only among themselves. This provided the perfect opportunity for genetic disorders to become established. It has been known for many years that Tay-Sachs disease, which prevents the nerves of babies and children from working properly, is especially prevalent among Ashkenazi Jews. In Britain, the National Health Service website advises,

Speak to your GP if: you're planning a pregnancy and you or

your partner have a Ashkenazi Jewish background

There is a predisposition towards other lethal diseases among Ashkenazi Jews (2). In the mid-1990s it was discovered that Ashkenazi Jews had a one in 40 chance of carrying a mutation on the BRCA 1 and 2 genes; thus greatly increasing the chances of women developing breast or ovarian cancer (3). These became known as the Ashkenazi BRCA Mutations and meant that the Ashkenazi Jews had the highest risk of any population for this problem.

Thinking now specifically of marriages between cousins, we observe that such marriages have traditionally been more popular in this community than most others. It was noted in nineteenth century England that cousin marriages were three and a half times more common among Jews than they were between Christians (4). Marriages between cousins, although legal in most countries, are sometimes looked at a little askance as tending slightly towards the incestuous. The mild disapproval sometimes evinced is perhaps associated with the increased risk of genetic problems being passed down. Even more likely to raise eyebrows among the average person is the fact that the Talmud, the ancient guide to the practice of Judaism, specifically allows marriages between a man and his sister’s daughter; which is illegal in most countries and even more hazardous from a genetic perspective.

The situation with genetic disorders is even worse in England’s Pakistani community, who have a very high rate of cousin marriages. In 2014 the results of a research project into the alarming number of young children dying in the Midlands city of Birmingham was published. The report of the work, which was carried out in large part by the Enhanced Genetic Services Project, under the auspices of the National Health Service in Birmingham, was shocking. It was found that the rate of stillbirths and infant deaths ‘definitely or probably due’ cousin marriages between people of Pakistani heritage was 38 times that of white European babies (5). Nor are these the only ill-effects of cousins marrying each other in this community.

Since over half of schoolchildren of Pakistani heritage in Britain are the product of cousin marriages, the incidence of genetic birth defects is 10 times that of the white, British population. Academic under-achievement in this community is widespread and, according to a survey of children in English schools in 2011, ‘Profound multiple learning difficulties are more common among ‘Pakistani’ and ‘Bangladeshi’ children’ (6).

The problems arising from widespread marriages between cousins of those in Britain’s Pakistani and Bangladeshi communities make this a matter of public concern, rather than a private matter between individuals. This is because the National Health Service, social services and the educational system are in the position of picking up the pieces, so to speak. In short, the cost of such marriages must be borne by all taxpayers and this places a burden upon the general population, who are expected to bear a burden created entirely by a cultural tradition among certain ethnic minorities. At the very least, it is not unreasonable for a debate to be held about the wisdom of such marriages and the extent to which they should be tolerated in a sophisticated, modern society.

1. Barton, Simon (2009) A History of Spain, London: Palgrave Macmillan.

2. Goodman, R.M. (1979) Genetic Disorders among the Jewish People, Baltimore: Johns Hopkins University Press.

3. Antoniou, A.C., Gayther, S.A., Stratton, J.F., Ponder, B.A., et al. (2000) Risk models for familial ovarian and breast cancer, Genetic Epidemiology, 18, 2, 173–90.

4. Jacobs, Joseph (1891) Studies in Jewish Statistics, London: D. Nutt.

5. Alberg, Corinna; Kroese, Mark; Burton, Hillary (2014) Enhanced Genetic Services Project Evaluation Report, Cambridge: PHG Foundation.

6. Emerson, Eric; Hatton, Chris; Robertson, Janet; Roberts, Hazel; Baines, Suzannah; Evison, Felicity; Glover, Gyles (2011) People with Learning Disabilities in England 2011, Bath: The Learning Disabilities Public Health Observatory.