Daniel Moynihan's report on the African American family was released in 1965. "Out of wedlock" births for this group were already at 25% and single-parent households had been rising gradually since 1880.  So these roots go back some time. Historically, African Americans have also lived in extended family structures with more frequency that other cultures, and single mothers tend to be connected in one way or another to those structures. There are other issues, of course--loads of them. 

I don't know what you mean by women becoming more like men. Men are not the standard. Human is the standard.