According to a PolitiFact check, published in the Atlanta Journal-Constitution on 8/26/15, there are only 33 countries in the world that have birthright citizenship that automatically makes anyone born in that country a citizen.
Most of the 33 countries are in the Western Hemisphere, including the U.S., Canada, Brazil, Mexico, and Argentina. Germany and the United Kingdom both confer citizenship to anyone if at least one parent is a citizen or a permanent resident.
This puts a little different spin on the current brouhaha over birthright citizenship, realizing that no country in Europe or East Asia has such a right. That doesn't change the way I feel about the mean-spirited, anti-immigrant furor out of which this arose -- nor the facts that the number of undocumented immigrants has actually declined.