London: The chances of having a baby with potentially life-threatening birth defects doubles in case of `first cousin marriages`, a study has revealed.
From a sample of nearly 11,000 births between 2007 and 2011, more than 2,000 babies were born to first cousin parents- predominately from the city`s large Pakistani population, the Independent reported.
Researchers from the University of Bradford and the University of Leeds found that the children of such unions had a six per cent chance of having a congenital abnormality, compared to an average 3 per cent chance.
The new "Born in Bradford" study suggested that kids born to parents who were not cousins but were closely related also had an increased risk.
The research was published in The Lancet.