U.S. immigration law allows certain noncitizens who are family members of U.S. citizens and lawful permanent residents to become lawful permanent residents (get a Green Card) based on specific family relationships. If you are The parent of a U.S. citizen (if the U.S. citizen is 21 years of age or older), you can become a lawful permanent resident (get a Green Card) based on your family relationship if you meet certain eligibility requirements.