I think you need to recheck your statistics. The fact is, in those Scandinavian countries, they have a much higher rate of out of wedlock births than the rest of Europe and more than 60% higher than the US.
I think you need to recheck your reading comprehension. I pointed out that the Scandinavian demographics prove there is no inherent correlation between births being "out of wedlock", and children living with both natural parents. Scandinavia is full of male-female couples living together with their biological children, without possessing a government-issued marriage certificate. And the U.S, in which few jurisdictions recognize gay marriages or "civil unions", is chock full of children living with only one parent, either after divorce, or in situations where the father was never living with the mother in the first place (much less married).