Most of this has been widely publicized. Women make less money than men, and men are terrible at paying child support especially if they divorced their first wife and married a trophy. Most trophy's get very agitated when they realize that their income if they work is also factored in to the amount the husband can now afford for child support. They then don't want the husband to have to pay child support. State's are typically lax in collecting and enforcing child support. So between the lower pay of women generally no matter what they do, and the unwillingness of many husbands to pay for the support of the children they fathered after they get divorced, the children of divorced parents who live with their single mothers, are more likely to live in poverty.
It's not rocket science.
Unfortunately, women who come out of messy relationships generally are not prone to jumping back into another relationship so they generally don't get re-married right away. In addition, there are numerous statistics that show that women with daughters have a much harder time finding a second husband, than women who have sons. Go figure! So the best news is that people are having fewer children and there are fewer divorces leaving single parents with children. But the problem is still wide-spread! And until women attain workplace wage parity with men they are going to have less money than men. And until the State's all start a more ruthless enforcement of child support, more women with children are going to continue to live in poverty. And the problems associated with poverty and single parenting will persist.