Almost 25% of Rotterdammers with a Turkish background and 20% of those with Moroccan origins marry relatives, reports Tuesday’s Volkskrant.

This means that their children have a higher chance of developing birth defects – from mental deficiencies to inherited anaemia and even death.
A public information campaign and further genetic research is needed to combat the problem, says the government’s health and environment council RIVM which looked into the issue on behalf of the health ministry.
The RIVM’s research follows a recent report that indicated a higher death rate among non-western immigrant babies.
The paper points out that it is difficult to make the calculations because there are no national statistics about birth defects, and inter-familial marriage is not registered.
Nevertheless, it says, research does show that non-western immigrants who have a child with birth defects are six times more likely to be related than their native Dutch counterparts.
The other reason for the higher death rate among ethnic minorities is poor social economic conditions.