Source: http://barrylieber.com/about-immigration/petitions-of-parents-for-children/
Timestamp: 2019-04-23 06:35:58+00:00

Document:
How Do I Bring My Child, Son or Daughter to Live in the United States?
An unmarried “son or daughter” is a person who was once a “child” but who is now 21 years of age or older. A “married son or daughter” is a person who has a recognized parent-child relationship, but who is also married, regardless of age.
A legal immigrant (or “lawful permanent resident”) is a foreign national who has been granted the privilege of living and working permanently in the United States. There is a three-step process for your child or son or daughter to become a legal immigrant.
The State Department must then give your son or daughter an immigrant visa number, even if he or she is already in the United States. If you are a U.S. citizen and the child is both under 21 years of age and unmarried, a visa number is not required.
If your child or son or daughter is outside the United States, he or she will be notified to go to the local U.S. consulate to complete the processing for an immigrant visa when one becomes available. If your child or son or daughter is legally in the U.S. when an immigrant visa number becomes available (or if one is not required), he or she may apply to adjust status to that of a lawful permanent resident using the Form I-485.
The Immigration and Nationality Act is the law that governs the admission of all immigrants to the United States. For the part of the law concerning immigrant status for children, sons, and daughters, please see INA § 202, INA § 203 and INA § 204. The specific eligibility requirements and procedures for qualifying for immigrant visas and permanent residence are included in the Code of Federal Regulations (CFR) at 8 CFR § 204.1, 8 CFR § 204.2, 8 CFR § 204.3 , and 8 CFR § 245.
Who is Eligible to Be a Sponsor?
A U.S. citizen’s unmarried, minor child is considered an immediate relative, does not need a visa number, and is eligible to receive an immigrant visa immediately.
Otherwise, sons and daughters of U.S. citizens will be eligible for a visa when their priority date is listed on the Department of State’s Visa Bulletin .
If your unmarried, minor child was admitted or paroled into the U.S., he or she may file the Form I-485, Application to Register for Permanent Residence or Adjust Status, at the time you file your Form I-130, Petition for Alien Relative.
If your unmarried, minor child has children, see the petitioning section on beneficiaries.
A lawful permanent resident may not petition for a married son or daughter.
If you had children before you became a permanent resident and you did not immigrate as an immediate relative of a U.S. citizen, your unmarried, minor children may be eligible to receive following-to-join benefits. This means that you do not have to submit a separate USCIS Form I-130 (Petition for Alien Relative) for your children, and your children will not have to wait any extra time for a visa number to become available. See the Petitioning Procedures for more information on following-to-join benefits. Otherwise, children of LPRs will be eligible for a visa when their priority date is listed on the Department of State Visa Bulletin.
To petition for your child, son, or daughter to live in the United States permanently you should file a form I-130, Petition for Alien Relative. To find out how to file this petition, please see Petitioning Procedures, which will help you identify what you need to do.
Exception: If you are a U.S. citizen petitioning for an orphan, you must file a petition to classify an orphan as an immediate relative. The petition is Form I-600, and the form to use for advance processing is Form I-600A.

References: § 202
 § 203
 § 204
 § 204
 § 204
 § 204
 § 245