Keep in mind, the social worker will present a case to you and if you feel that you're not prepared for it, you can tell them no. Like Wanda said, there's a lot of perfectly normal kids in care and just because a baby was born with FAS or a drug addiction doesn't necessarily mean that they will...
I tell anyone I know that wants to adopt a child to consider adopting through the foster care system. A lot of parents are foster-to-adopt and if possible, our social services will try to give them cases where they're pretty sure the case will move to termination and adoption. (Keep in mind...