[aruanan]

The truth is, no such automatic citizenship is granted to children of noncitizens just because the birth took place on US soil. The child must swear allegiance in a formal ceremony upon reaching his 18th birthday.

Not so. If, perhaps, the kid went back to the parents' country, then on his 18th birthday he could make a choice. Otherwise, if he grew up here in the U.S. there would be no such swearing in a ceremony, formal or informal. His birth certificate would indicate a U.S. birth, making him a natural born U.S. citizen just like everyone else born here regardless of their parentage.

[GingisK]

His birth certificate would indicate a U.S. birth, making him a natural born U.S. citizen just like everyone else born here regardless of their parentage.

That is operationally correct, but that method is not Constitutional.