Outside actual poverty, the kids are still getting fed, going to school, maybe they're one console generation behind two-parent households but even that's not such a big deal now...
Kids from single parent households are something like half as likely to graduate high school and considerably more likely to end up in prison. It's a big deal.
To be fair to SamReidHughes, almost none of that can be attributed to the fact that the household is missing a parent. Kids from single-parent households where the missing parent is missing through coincidence, such as by dying in an accident, perform at the same level as kids from two-parent households.
Yeah, attempts to show causality there have fallen down. And single parents aren't some abstract concept either; they largely aren't neglecting their kids.
And yet no sane parent would want their children to grow up in a single parent household. Studies don't show everything. Anyone with two eyes and ears can see that single parent households are not good for children. Most children that have grown up in a single-parent household can speak to this. If a culture has a high proportion of single-parent households, this needs to be addressed.