General Discussion

Most of the world uses the Jus Sanguinis model, where you derive citizenship from your parents. Some, like France and Britain, use a form of birthright citizenship but limit it to people who are legally settled in the country. Australia uses a combination of both models, where you get automatic citizenship if one of your parents is a citizen, but can claim birthright citizenship if you can show that your parent was raised in Australia (even if they weren't citizens). The Australian model was designed to prevent the formation of a non-citizen underclass.

The last time I looked, the only nation outside of the Americas that followed the "If you're born here, you're a citizen" model was Pakistan. India used to have it as well, but they abolished it quite some time ago.