That sounds like an empirical claim. Do you have any evidence to back that up?

The evidence in the other direction showing marital status is linked with child poverty is pretty clear. Census data shows that poverty rates are five times higher for children of single mothers (1).

Maybe the mechanism isn't clear or something, but the data is stark enough to deserve an explanation about why marital status isn't important to kids.

(1) http://educationnext.org/files/ednext_XV_2_mclanahan_fig04.j...

I took the parent comment to mean that being married itself shouldn't provide any more benefits than just being in a stable, long-term relationship. To your point, I agree that having a marriage ceremony probably helps maintain the relationship due to social pressure.

I would be interested to see research comparing the children of married couples to those of unmarried stable long-term relationships. My hypothesis is that the outcomes would be similar.

> I took the parent comment to mean that being married itself shouldn't provide any more benefits than just being in a stable, long-term relationship.

Understood. I still think it's fair for the burden of proof to fall on the people trying to explain away current demographic trends. Just because possible mechanisms don't line up with expectations doesn't mean the outcomes aren't actually happening.

And, at some point, there is a distinction without a difference when talking about long-term monogamous cohabitations that do or do not involve a wedding ceremony. In common law, it would be a marriage either way. Maybe the real question is why common law marriages aren't recognized more often now.