In some ways, society has come a long way since the Middle Ages, when children were regularly sent out by their families into indentured servitude and and babies were sent away to wet-nurses. In others we have not.
The subject of human trafficking has been a hot topic of discussion recently, and I have heard horrendous stories of children and adults sold as slaves, trapped in shocking conditions, abused and used, sold as commodities, raped, and beaten. At least recent public discussion has lead to broader awareness of these terrible facts, and at least some policy and enforcement work is being done to attempt to improve them.
However, the type of child cruelty described in this article and its extent, is not part of the public discourse: The Child Exchange, America's Underground Market for Adopted Children, Reuters, Megan Twohey, September 9, 2013.
Apparently, there are people who regularly engage in what is termed "rehoming children", meaning advertising for replacement children who are the products of failed adoptions, often on the internet. Of course, these are children whose parents originally placed them for adoption. These children then must relive the pain of being rejected. Sometimes, adoptions fail, and adoptive parents indicate that they cannot handle parenting the child and have made a mistake. Predators may prey on this sad situation and these children may be placed with people who specialize in rehoming cases, such as the Easons described in the Reuters article. There is no government review or oversight of these homes, and often these parents may have previously had their parental rights terminated through the child welfare system as to their own children.
Please take a look at the sad story of Quita, a girl adopted from Liberia, then rejected by her adoptive parents and sold on the internet in an unregulated transaction.