Cousin relationships are no longer a “majority” in Bradford’s Pakistani female community amid growing awareness of the risks of birth defects.
A decade ago, a government-funded surveillance project found that 62 percent of women of Pakistani descent were in blood relationships.
This figure has since fallen to 46 percent, researchers say.
It comes amid pressure to ban first cousin marriage.
Independent MP Iqbal Mohamed received huge criticism yesterday after speaking against the motion.
A senior Conservative said it was “shocking” that an MP “defended this disgusting practice”.
Experts began tracking the prevalence of consanguinity in Bradford, home to one of the largest Pakistani communities in the United Kingdom, in the late 1990s.
Nearly 12,500 pregnant women were questioned about their marital status with the father of their child.
The Born in Bradford study was subsequently repeated with another cohort of 2,400 women between 2016 and 2019.
The final results were published last month by Wellcome Open Research, a platform run by the prestigious Wellcome Trust.
Sharing an earlier version of the results with the BBC last year, lead researcher Dr John Wright spoke of the “significant change” seen in just under a decade.
He described cousin marriage as having gone from being a “majority activity to now being a minority activity.”
Dr Wright added: “The effect will be that there will be fewer children with birth defects.”
It was said that the Born in Bradford figures may indicate that the number of Pakistanis marrying cousins across the UK is also falling.
The reasons behind the drop are believed to include high educational attainment, stricter immigration rules and changes in family dynamics.
In their study, the team said: “It may be that we are seeing generational changes and new social norms evolving.”
“But these changes should be monitored to see if they are indicative of lasting change and should be considered in other settings where inbreeding is common to see how widespread these reductions in inbreeding are.”
More than half of the residents living in the Bradford West constituency, represented by Labor MP Naz Shah, are Pakistani.
The figure is 36 per cent in Bradford East and almost 17 per cent in Bradford South, the city’s two other constituencies.
This map, drawn up by Professor Alan Bittles, an Australian genomics expert, shows rates of consanguineous marriage, that is, between cousins, around the world.
Birmingham also has a large Pakistani community, with up to 40 percent of people belonging to that ethnic group in some parts of the city.
Cousin marriage was once common among Britain’s upper classes.
Historically it was considered a way to consolidate alliances and keep wealth and land in the family.
Despite having gone out of fashion, the practice is still common in some communities, such as travelers.
Queen Victoria and Prince Albert were first cousins and shared a set of grandparents.
The reality of “extreme” inbreeding in the UK was exposed before Covid.
Scientists who analyzed the genes of 450,000 Britons believed that 125 had parents who were first- or second-degree relatives.
This was equivalent to a rate of one in 3,600.
When extrapolated to the general population, the 2019 study, published in the journal Nature Communications, was reported to mean that 13,000 Britons were conceived through extreme inbreeding.
First-degree relationships include those between parents and children, while second-degree relationships include more distant, but still genetic, close relatives, such as half-siblings.
The University of Queensland authors noted that given the nature of the subject and the limited range of Britons included in the sample, the actual rates could be significantly higher or lower.
Incest (sexual relations between immediate relatives) is illegal in the UK even if it is consensual.
Marriages between certain blood relatives, as well as some domestic relationships, are also illegal.
However, it is legal to marry your cousin in the UK.
Former Conservative minister Richard Holden yesterday proposed a bill to completely ban the practice.
Holden said now was a “sensible time” to broach the issue: “People already think it’s illegal and then are surprised when you mention it’s not.”
He pointed to evidence showing it increases the risk of birth defects and said it can “reinforce negative structures and control women.”
Mohamed, representing Dewsbury and Batley, suggested MPs should avoid “stigmatising” the issue, which is seen as “very positive” in some communities.
Rather than banning it entirely, he said a “more positive approach” including advanced genetic testing for future married cousins would be more effective in addressing related issues.
Mohamed, who is part of the Independent Alliance of MPs including former Labor leader Jeremy Corbyn, faced criticism from senior Conservatives for defending the practice.
Conservative justice spokesman Robert Jenrick said: “It is shocking that an MP would defend this disgusting practice which is linked to birth defects and abusive relationships.”
‘We know this is causing immense damage. This practice has no place in the UK.’
Labor refused to back measures to ban first cousin marriages.
Worldwide, one in 10 people is believed to be the result of a blood union.
Estimates of the prevalence of consanguineous marriage around the world vary.
According to studies, Pakistan has one of the highest rates in the world, with 65 percent unionized.
They are followed by India (55 percent), Saudi Arabia (50 percent), Afghanistan (40 percent), Iran (30 percent), and Egypt and Turkey (20 percent each).
Data suggest that the risk of a child of first cousins developing a genetic condition is up to 6 percent, twice that of children of unrelated parents.
While this means that most children born in such circumstances will be healthy, the increased risk is undeniable.
In addition to birth defects, possible conditions for which children of first cousins are at increased risk include developmental delays and ongoing genetic disorders.
These can include conditions such as blindness, low IQ, cleft palate, heart problems, cystic fibrosis, and even an increased risk of infant death.