DOMA and Prop 8. Both History.

[kandrathe]

Marriage isn't really the issue then. It's that these married cousins are procreating and having higher rates of offspring with defects. If they didn't have offspring, then it wouldn't be an issue. Rather than try to control marriage, or intercourse, why not change your immigration rules?

I read about similar issues in other European nations, where the same consanguinity problems (increase in birth defects) are arising due to immigration policy and the immigrants social norms. The public policy issue you've raised is the health care burden upon the Dutch society, rather than any sense of moral outrage. I suspect however, that for some people, like Mr. Wilders, there is also an anti-immigrant (nationalistic) sentiment permeating their call to action. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3419292/

So, how about changing the rules so that a naturalized immigrant cannot confer citizenship upon their spouse. The immigrant spouse must pursue naturalization like any other immigrant. A natural born citizen would be able to confer the short cut to naturalization.

But then again, this may also lead to other unintended consequences, where people have many natural born "Dutch" children and marry them off at a young age to older relatives to get them into the country. Such is the nature of law, it makes people adapt their behaviors.