That doesn't sound like any Scandinavian system I'm familiar with. (I'm Swedish.)

Our legal system isn't based on common law. It's a mish-mash of clan thinking with a frosting of Code Napoleon. (Which is why you can't disinherit your children, you can only will away a quarter to a half of your possessions and wills have only been around for little more than a century. Possessions, land in particular, belonged to the clan and not to the person.) Child support is a relatively recent thing, but bastards became legitimate children when the mother married the father.