1. Children as Immediate Relatives of U.S. Citizen 

Unmarried children under 21 year old of U.S. citizens are eligible to apply for permanent resident status as immediate relatives. Immediate relatives may immigrate to the United States on a family based petition. This is the most attractive category, since there is no limitation to the number of immigrants who may qualify under this category and, in most cases, visa numbers are immediately available for these individuals to apply for lawful permanent residence. Immediate relatives include spouses, children and parents of U.S. citizens. 

For immediate relative, to qualify as a "child" of a U.S. citizen, the person must be the son or daughter of a U.S. citizen, and the immigration law defines a “child” as an unmarried person under the age of 21 (a minor) who is: 

• A child born to parents who are married to each other (born in wedlock);

• A stepchild if the marriage creating the step relationship took place before the child reached the age of 18;

• A child born out of wedlock (the parents were not married at the time the child was born). If the father is filing the petition, the proof of a real and established relationship with the father must be supplied;

• An adopted child if the child was adopted before the age of 16, and has lived with the adoptive parents in their legal custody for at least two years;

• An orphan under the age of 16 when an adoptive or prospective adoptive parent files a visa petition on his or her behalf, who has been adopted abroad by a U.S. citizen or is coming to the U.S. for adoption by a U.S. citizen, or

• A child adopted who is under the age of 18 and the natural sibling of an orphan or adopted child under the age of 16, if adopted with or after the sibling. The child must also otherwise fit the definition of orphan or adopted child.

2. Children as Close Family Members of U.S. Citizen or Permanent Resident

The close family members of a U.S. citizen or permanent resident can qualify to immigrate to the United States, but they are subject to a numerical limit of immigrant visas available to them each year. Generally, the higher the preference, the quicker the alien will be eligible to receive a Green Card. The relatives in categories must wait for a visa to become available according to the following preferences:

• First preference: Unmarried Children over 21 year of age of U.S. Citizens (23,400 per year, plus unused visas from the Fourth Preference);

• Second Preference: Spouses and unmarried children (regardless of age) of U.S. permanent residents (114,000 per year, plus unused visas from the First Preference);

• Third Preference: Married sons and daughters of U.S. citizens, including their spouses and their minor children. (23,400 per year, plus unused visas from the First and Second Preferences);

• Fourth Preference: Brothers and sisters of U.S. citizens, including their spouses and their minor children. (65,000 per year, plus unused visas from the First, Second, and Third Preferences).

3. The Eligibility to Sponsor a Child to Immigrate to the United States

To be eligible to sponsor a child to immigrate to the United States, you must meet the following criteria:

• You must be a U.S. citizen or a lawful permanent resident of the United States, and be able to provide documentation to prove your status; 

• You must prove that you can support your relative at 125% above the mandated poverty line.

• Your can legally prove that you share the child/parent relationships.