https://datacenter.kidscount.org/data/tables/107-children-in...
http://www.ncsl.org/research/elections-and-campaigns/felon-v...
Why do you think single parenthood is rising, or that adoption opportunities are drying up? I doubt there has been a time in the history of mankind that is more accepting of single parenthood, or where it's been more possible to raise a child on your own. Women by and large aren't financially obligated to give up their children in this day and age, and with society becoming more secular it's socially more acceptable to be a single parent.
Further, what makes you think any institutional policy, or anything at all, can fix single-parent households having worse outcomes than two-parent ones? It's just simple logic: two parents tend to meet children's needs better than one because there are two of them.
This and the other sibling comments seem focused on single-parenting and not the rest of the GP argument (which I still maintain is unsupported).
Perhaps...
> It is because the extremely high percentage of Black kids living under single parenthood family [1]
This is wildly unsourced - what data do you have (ideally across nations/racial categories) for this?