You are going to have to go to the U.S. Consulate and prove to the US Consulate that your child is a United States citizen. Whether or not they are a United States citizen is not a given. It depends on when they were born, what year, and how long you have been physically present in the United States. If you’ve been physically present your whole life and you just happen to be overseas for a year or on vacation and gave birth, then 9 times out of 10, you’re not going to have an issue with getting proof that your child is a United States citizen.
What immigration is going to want to see, or the Consulate is going to want to see, is proof of your actual residence, or physical presence in the United States. If the requirement, again, depending on the year that your child was born, was that you had to be living in the United States physically for five years prior to the child’s birth, you’re going to need evidence of that physical presence. That’s usually done by tax returns, bank statements, school records, etc. to show that you’re physically present. You are also going to have to fill out an application swearing to your dates of physical presence in the United States. If it’s a father who’s applying for citizenship for the child, they also might want to have a DNA test to make sure he’s actually the father and, of course, they are going to want to see the birth certificate. Whether or not your child is a citizen, and the evidence that you need to prove it can be very complicated, and is not as easy as we all think. It’s important to discuss your situation with an immigration lawyer to make sure that your child is a United States citizen and what evidence is necessary to prove it. If you have questions, please contact my office and I’d be happy to discuss your situation with you.