I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.
U.S. Citizens
If you are a U.S. citizen, your minor child (unmarried and under 21 years of age) will be considered an "immediate relative" and will receive an immigrant visa to enter the United States. To receive an immigrant visa you must prove your relationship to your child and your child must be admissable under the immigration law. You will need to file a Form I-130 Petition for Alien Relative. You may also file a petition for an unmarried son or daughter over the age of 21 or a married son or daughter under the preference classifications by filing a Form I-130 Petition for Alien Relative. After the petition is approved by the Immigration and Naturalization Service, the State Department will give your son or daughter an immigrant visa number as soon as a number is available. You may file a Form I-485 Application for Adjustment of Status to Permanent Resident at the same time. However the application for adjustment of status will not be considered until a visa number is immediately available and the petition for immediate relative or preference classification is approved.
For an overview of immigration, please see the chapter and tables on immigrants. (You will need the Adobe Acrobat Reader plug-in, available here.) in the INS Statistical Yearbook . For more information on immigrant visa numbers, please see How Do I Get an Immigrant Visa Number? For more information on adjusting to permanent resident status, please see How Do I Become a Lawful Permanent Resident while in the United States?
This is the link for the above paragraph:
http://www.ins.usdoj.gov/graphics/howdoi/child.htm
This link will show you the worksheet where you can find this informatio out. There are steps to make sure the citizenship status happens - but it is not automatic.
http://www.ins.usdoj.gov/graphics/services/natz/wsinstruct.htm