A guardian is a legally appointed adult representative for a child. The guardian's function is to ensure that a child’s rights are upheld and the child's best interests are protected. The existence, process and duties of a guardian will vary from country to country. When no formal guardian system exists, alternative systems can be created for having a legally recognised representative for a child. This is particularly important when children are likely to be orphaned or made vulnerable by HIV/AIDS, or unprotected by adult caretakers such as child-headed households.