In the United States, laws regarding age requirements on adoption vary from state to state, but one must be at least 18 years of age to adopt a child. The requirement of being 21 years of age, however, is much more common.
Age is seen as a sign of responsibility, which dictates the adopter's ability to care for the child. This requirement is put in place to ensure that adopted children go to good homes with parents who are financially and emotionally stable. Typically, adoptive parents are between the ages of 25 and 50 years—old enough to be a college graduate, although that is not a requirement, but young enough not yet to be nearing retirement.