If you are adopted those parents become your legal parents. If fostered then your birth parents are still your legal parents. There are different types of fostering, emergency, short term and long term. Long term is sometimes permanent, it might be if the child is older when they are first fostered and they do not want to be adopted but still stay with their foster family until they are an adult. Children who are going to be adopted are also sometimes fostered first while a new family is found for them. Hope that helps.