Ten years ago researchers studying the health of more than 30,000 people in Bradford found that about 60% of babies in the Pakistani community had parents who were first or second cousins, but a new follow-up study of mothers in three inner-city wards finds the figure has dropped to 46%.
The original research also demonstrated that cousin marriage roughly doubled the risk of birth defects, though they remained rare, affecting 6% of children born to cousins.