QUOTE(riblet @ Dec 7 2006, 10:36 AM)

I don't think anything happens when a parent naturalizes, I just researched a bit on this and didn't find anything useful. I believe they will have to file when they turn 18.
This is just false.
Look at the law below:
http://www.schulzlaw.com/mschulz_citz.phpDerivation of US Citizenship as a Minor through Naturalization of One or Both Parents
Derivation means that the minor automatically becomes a citizen when the parent or parents naturalize. There is no requirement for the minor to apply to the USCIS for citizenship, instead the minor can apply directly for a US passport.
After February 27, 2001:
The child must be unmarried;
The child must be under 18;
The child must have at least one US citizen parent (by birth or naturalization);
The child must be currently residing permanently in the US in the legal and physical custody of the US citizen parent
The child must be a lawful permanent resident of the US; and
If adopted, the child must satisfy the requirements applicable to adopted children under US immigration law.
The child can still do an N-600 to get his or her certificate if they please.