Economic incentives aren't going to encourage someone to not sell their child for deplorable purposes; if you don't emotionally care for your child, money isn't going to make you care. On the other hand, if you can use a non-profit to pay terrible/uncaring/abusive parents to hand over their children voluntarily (surrendering parental rights) and to get sterilized to prevent the harm of any more children, that is a cause I would write checks to all day long.

Disclaimer: I am a parent, and have fostered neglected children.