But then we have to start asking questions about why a woman is a single mother. Is it better for children to be in a single parent household or in one where he mother is abused? Or one where the children are abused? Is living in a household with a non-contributing partner superior?

Can we control for confounding variables like education level and age at first conception because maybe the answer isn't "single parenthood is awful" but "women shouldn't have children so young" or "it turns out poor people just do worse than wealthy people". The first likely boils down to the 2nd.

I have seen so many varieties of single motherhood and couple parenthood that I'm not convince that single parenthood is inherently a problem. I think it's more poverty. Single motherhood often couples with poverty, although not always now that women are more educated. But I've seen dual income households that matched a single parent household have the same kind of struggles.

Perhaps we should just ask why our social net is so weak that being a single earner means you can't raise a child. Anyone can lose their partner and they shouldn't have to scramble to pick literally anyone just to ensure their kids are cared for.