"The further back in history one goes, the lower the level of child care, and the more likely children are to be killed, abandoned, beaten, terrorized, and sexually abused. "

I'm not so sure that's the case if you count "prehistory" with "history" as I do. from the book The Ohlone Way, I got a sense that children in the northern California coastal tribes were very well cared for. I can't say how well that extrapolates to other indigenous peoples, I'm not well read on that subject.