You can become a US citizen either by birth or through naturalization. If you were born in the US, you automatically become a citizen of the US. Naturalization is a process where a person not born in the US becomes a citizen voluntarily. Children born outside US to US citizen parents can claim US citizenship through their parents’ status subject to certain requirements. This also depends on the laws in effect at the time the child was born.
If you were born in the United States, you can just apply for a US passport as a proof of your citizenship status in the US. You need to file Form N 600, the citizenship application, if you want to document your US citizenship status based on your parent(s)’ status as US citizen(s). To be eligible to file Form N 600, the citizenship application, it normally requires a combination of at least one parent being a U.S. citizen when you were born and having lived in the U.S. or its possessions for a given period of time. Additionally, children born outside the US may become citizens after birth based on their parents’ citizenship or naturalization depending on various factors.
As mentioned earlier, you can automatically become a U.S. citizen if you meet certain conditions. You should be under the age of 18 and at least one parent of yours should be a U.S. citizen, whether by birth or naturalization. You should reside in the United States in the legal and physical custody of your U.S. citizen parent subject to lawful admission for permanent residence.
Additionally, to qualify as a “child” for purposes of getting a certificate of citizenship through parents’ status, you should not be married. Also, if you were born out of wedlock, you should be “legitimated” while under the age of 16 and while in the legal custody of the legitimating parent. However, a stepchild who was not adopted will not qualify as a “child” under this section. If you satisfy these requirements before turning 18, you automatically obtain US citizenship without having to file an application. However, to get a citizenship certificate from USCIS, you must file Form N 600, the certificate of citizenship application.
Per the Child Citizenship Act, individuals who were age 18 or older on February 27, 2001 are not qualified for citizenship. One who was over the age of 18 as on February 27, 2001, may be qualified to apply for a citizenship certificate under the law in effect before the enactment of the Child Citizenship Act.
Also, biological or adopted children who regularly reside outside of the United States may qualify for citizenship. However, you must meet certain requirements to get one. At least one parent of yours should be a U.S. citizen or, if deceased, the parent was a U.S. citizen at the time of death. Per the law, your US citizen parent should have been physically present in the United States or its outlying possessions for at least 5 years, at least two of which were after reaching the age of 14. And of course, you should be under the age of 18 years. Additionally, you should be residing outside of the United States in the legal and in the physical custody of the U.S. citizen parent and finally you are temporarily present in the United States after having entered lawfully and maintaining lawful status in the US.