Child immigration can be a complex issue. It is not only an issue for those who travel to the United States but it can also be an issue for U.S. citizen parents who have a child residing outside of the United States. 

The U.S. Citizenship and Immigration Services explains how children who reside outside of the U.S. may be eligible for naturalization. 

Eligibility requirements for children 

If a child resides outside of the U.S. he or she qualifies for naturalization if there is a U.S. parent through birth or naturalization. The child must be under the age of 18 and must be under the custody of the U.S. parent or under the custody of a person who does not object to the U.S. citizen applying for naturalization. 

Children must be physically present and maintain a lawful status when there is an approval of the application and when he or she becomes naturalized. Children who were born through ART may also meet the requirements for naturalization. 

Eligibility requirements for parents 

For a child to receive naturalization, the parent also must meet certain requirements. Parents must be present in the United States or one of its territories for at least five years. Also, parents must have spent at least two of those years in the United States after they turned 14. For military parents, any time served in the military, regardless of where he or she resides on military orders, counts. 

If the parents do not meet the requirements, the child may use the grandparents. The grandparent must meet the same requirements that the parents had.