Although the institution of the adoption of children exists in most countries, there are differing views as to the principles which should govern adoption, both in procedure and in legal consequences. The legal status of an adoptive child may be different from that of a natural child, and he may have restricted rights of inheritance. Since the natural mother's or the parents' consent is usually necessary, the adoption process may be hindered, or the parents may reclaim the child later. Some foster parents discriminate when choosing children, often leaving the unintelligent, less attractive, deformed or racially unacceptable children. In rare cases foster parents prove to be inadequate. Others effect a sham 'adoption', acquiring children for a price from poor parents for use as servants or possibly for sexual exploitation.