They need to learn that you are adults who will take care of them and not harm them. They need to learn that you are going to react differently than their parents did. If they do not learn this, they may provoke you into abusing them in the same way their parents did. They are not being intentionally perverse. They are responding to a drive which in psycho-analytic terms is called repetition compulsion .
Repetition compulsion describes a tendency most people have to repeat certain patterns of behavior.
Children who have been abused seem driven to relive their past. They provoke people into treating them just as their parents did. The reasons for this are complex. In oversimplified terms, these troubled children recreate the very situations which have frightened them, hoping this time they will be less frightened. This time maybe they will get it right .