An interesting article by Stanley Kurtz about Nordic countries’ experiment with gay marriage. He claims that gay marriage, far from strengthening traditional marriage, has contributed to the latter’s decline.
I don’t think Kurtz proves his case. He does prove that gay marriage has done nothing to stop the collapse of the family in Nordic countries. However, I don’t think you can make the leap to say that it has hastened it, either. More interesting are some other points, particularly that mothers working outside the home, bastardy, and weak family bonds are caused or at least aggravated by a huge welfare state. (In other words, if you’re a Catholic Democrat, you are in favor of creating conditions where sexual sins will flourish.)
Here’s some good news, though, about the Nordic folkways and their growth in Europe:

Yet the pattern is spreading unevenly. And scholars agree that cultural tradition plays a central role in determining whether a given country moves toward the Nordic family system. Religion is a key variable. A 2002 study by the Max Planck Institute, for example, concluded that countries with the lowest rates of family dissolution and out-of-wedlock births are “strongly dominated by the Catholic confession.” The same study found that in countries with high levels of family dissolution, religion in general, and Catholicism in particular, had little influence.

My ancillary theory, based on being in Norway for a couple of weeks, is that Scandinavians have a very high incidence of beautiful women in their population, and that it would take severe mortification to avoid temptation. But my view has not gained ground among social scientists.