Permanent residents of the United States (green card holders) may petition for his/her spouse, children (FB-2A) and unmarried sons and daughters (FB-2B) to immigrate to the United States. It is important to distinguish between “children” and “sons and daughters”. Children are unmarried and under 21, whereas sons and daughters are 21 or older, or married, or both.
Turning 21 years of age: If the unmarried child of a permanent resident, turns 21 years of age, the process of becoming a permanent resident or obtaining an immigrant visa may be delayed. The son or daughter will no longer qualify as an Unmarried Child of a Lawful Permanent Resident and will convert to the category of an Unmarried Son or Daughter of a Lawful Permanent Resident (F2B). This change in categories may result in longer wait times until an immigrant visa becomes available.
Getting Married: If the unmarried son or daughter of a permanent resident gets married prior to becoming a permanent resident, he/she will no longer qualify for permanent residence through your permanent resident family member. There is no visa category for a married child of a permanent resident.
If the Permanent Resident Relative Becomes a U.S. citizen: If the permanent resident relative that petitioned for you becomes a U.S. Citizen, your preference category will change to that of a relative of a U.S. citizen and a visa may be available sooner.