Tragedies will occasionally come out of left field, so I believe you can find real hard luck cases where everything was sunshine and rainbows when the couple decides to have a kid. But based on the people I've known personally the people with messed up lives are a subset of the people make consistently poor decisions. I bet that 9 single parents who are struggling financially out of 10 have some identifiable poor choice you could find if they were totally open and honest about their history. Does she have a 6 month emergency fund, health insurance, life insurance, disability insurance, a large enough home, home insurance, a stable marriage, stable employment, flex in the budget? I think if you restrict to looking at parents who fit those criteria prior to the decision to have kids, the sliver who become this down on their luck is staggeringly tiny. And the parents who don't fit these can't afford kids.