Bradford's cousin marriage boom

The tradition of marrying a cousin is becoming more entrenched among British-born Pakistanis living in Bradford than it was a generation ago, writes Winifred Robinson.

 

Note: This item is extracted from the BBC Radio 4 website

 

This has been the surprise finding of the Born in Bradford research project. It's a huge long-term study of 14,000 mothers and babies in the city, the largest ever undertaken in the UK. Half of the families in the project are Asian.

 

Cousin marriage has important implications for health because marrying a cousin increases the risks of passing on genetic disorders. Bradford has three times the national rate among children for disabilities including deafness and blindness.

 

Globally, cousin marriage is practised by an estimated billion people, according to Professor John Wright, who is leading the Born in Bradford research project. It yields considerable social benefits - particularly in ethnic groups, where it is traditional for women to live with their in-laws.

 

"People marry cousins because it means you are coming into a family where everybody loves you," Professor Wright says, "and there are economic benefits of keeping land or other assets in the family".

 

The problem with cousin marriage is that it doubles the risk of passing on the recessive genes that lead to abnormalities. Cystic fibrosis is the one we all know about, where two healthy parents carry a recessive gene for the condition.

 

"If a cousin has a genetic variant that causes a disease and marries a cousin with the same genetic variant, then there is a one in four chance that the children will have that disease," Professor Wright explains.

 

On the face of it the risk is not great - a 4% risk of having a child with an abnormality if you marry a cousin, compared with 2% among the general population. But with repeated cousin marriage, the risks stack up in families with sometimes devastating results.