An adult who has physical custody of a child may have reasons for not wanting to become a legal guardian -- for example:

• The caretaker expects that the child's parents will not consent to a legal guardianship.
• Dynamics between family members are such that filing for a guardianship might set off a battle for legal custody. (This would be especially likely where a stepparent and one natural parent care for a child.)
• The caretaker doesn't want his or her personal life scrutinized in court or by a court-appointed investigator.

Some adults try to slide by and raise children (often grandchildren or other relatives) without any legal court authorization. If you go this route, you could run into problems with institutions that want authority from a parent or court-appointed legal guardian. Some communities and institutions, however, are very accommodating of people who are bringing up someone else's children. California, for example, has created a form that gives a nonparent permission to enroll a child in school and make medical decisions on the child's behalf without going to court. Research the laws in your state or talk to a knowledgeable family law attorney to find out whether there are ways for you to care for a child that don't involve becoming a legal guardian.