Citizenship at Birth

[manasecret]

Sounds fair, but getting into the nitty gritty, what are the criteria for being born a citizen? One parent must be a citizen? Two? That sounds awfully harsh to legal immigrants here.

Maybe one or both of your parents must be at least legal residents? In that case, forgery would I guess be an easy workaround.

What is the solution that is fair to legal residents but also has any teeth to keep illegal immigrants from figuring out how to illegally game the system? They're already illegally here, I can't imagine illegally forging documents to get citizenship for their kid would be a big hindrance. Then, once a kid has citizenship by forged documents, would it be right to take away that citizenship because of the parents doing wrong?

What do other countries do?