Finally there is the matter of arranged cousin marriages. Between a half and three-fifths of all Muslims, depending on the country, marry a first or second cousin. So-called consanguineous marriages pose a high risk of birth defects and naturally worry medical authorities. In the UK, the BBC reports, British Pakistanis—55 percent of whom have consanguineous marriages—account for 3.4 percent of all births, but for 30 percent of all birth defects.
