Unmarried Adult Sons or Daughters
U.S. Citizen: A United States citizen may apply for her/his children who are unmarried and under the age of 21 and also possibly stepchildren.
Lawful Permanent Resident: A lawful permanent resident may file for his or her foreign national child. The child of a lawful permanent resident is not an immediate relative and is assigned to the F2A category (spouse and children of permanent residents). The waiting time to get the green-card may be long depending on the Petitioner’s country. Current wait times can be found at the U.S. Department of State, The Visa Bulletin.
The above information is not legal advice, and should not be construed as such. Please contact an attorney to understand your immigration benefits.