Kids become chattel for human trafficking by migrants

Washington Post:

U.S. sees humanitarian crisis as migrants arrive with kids who are not their own

Smugglers in Central America charge less if a minor is part of the cargo. Some parents have given up their children to other adults to help the adult enter the United States. These cases can be complicated. The families face hunger and threats, and there are disagreements about paternity and allegations of abuse.

The way to stop this is to stop accepting illegal immigrant migrants and require that those immigrating to the US follow procedures and prove that the children with them are theirs.  In other words, the stated policy of the Trump administration would largely cure this problem.