64 countries, including the U.S., grant citizenship to babies born in the country, depending in parents’ status.
A general rule: if born in the Americas, you can claim “right of soil” citizenship in the birth country, regardless of parents’ status. If born in Europe or Africa, you only get citizenship if one or more of your parents is a citizen or permanent resident.
A complete list: Citizenship by Birthright: “Right of Blood” and “Right of Soil” if the Child is Born in a Foreign Country (immigrantinvest.com)
Am guessing a new trend will be expectant mothers who travel to other countries to give birth – so their child can get dual citizenship. Russian women have already been doing this: A different form of “immigration privilege” – Coldstreams Travel and Global Thinking
Once a child has citizenship, this often opens the door to the parents obtaining residency or citizenship.