Did the kid actually have to acquire US citizenship via naturalization or did it just take 2 years to prove that they were a citizen? Those two cases are really

Did the kid actually have to acquire US citizenship via naturalization or did it just take 2 years to prove that they were a citizen? Those two cases are really different. Even if you don’t have confirmation and proof that you are a citizen (eg by having a US passport), you are still bound by rules if you happen to be a citizen anyways (eg you have to file/pay US taxes). So a lot of kids find out later in life that they are actually natural born US citizens and have been evading US taxes illegally.