While the left has attacked the idea of ending birthright citizenship in the U.S. as “extreme,” globally the U.S. is one of few countries that actually grant automatic citizenship at birth to illegal immigrants.

As reports have indicated, the U.S. and Canada are the only two developed nations that grant automatic citizenship at birth to the children of illegal and temporary immigrants.

Last summer NumbersUSA investigated where countries across the globe stand on the issue of conferring automatic citizenship at birth to anyone born within their territories, also known as “jus soli” (a Latin term meaning “right of the soil”).

According to NumbersUSA’s list, the vast majority of counties do not adhere to jus soli. Of their list of about 190 countries, just 33 (including the U.S. and Canada) had a such a policy.

As John Skrentny, a sociology professor at the University of California at San Diego, has explained, for most of the world citizenship is granted base on blood or “jus sanguinis”.

“And the idea there is that the nation, the people are bonded together through ancestry. That is the most common conception of nationhood or peoplehood in the world,” Skrentny said to NPR in 2010. “The other notion of nationhood is generally understood as a civic notion of nationhood. And this is the idea that folks are bonded together by where they are, by locality and by the ideas that they might share.”

For example, there are no European countries that grant automatic citizenship based on jus soli.

In 2010 the Center for Immigration Studies did its own comparison of citizenship laws. That report yielded similar results as NumbersUSA.

As the reports’ author Jon Feere noted at the time, over the past several decades the trend has been to end “universal birthright citizenship.”

“Countries that have ended universal birthright citizenship include the United Kingdom, which ended the practice in 1983, Australia (1986), India (1987), Malta (1989), Ireland, which ended the practice through a national referendum in 2004, New Zealand (2006), and the Dominican Republic, which ended the practice in January 2010,” Feere explained in the report.

“The reasons countries have ended automatic birthright citizenship are diverse, but have resulted from concerns not all that different from the concerns of many in the United States. Increased illegal immigration is the main motivating factor in most countries. Birth tourism was one of the reasons Ireland ended automatic birthright citizenship in 2004. If the United States were to stop granting automatic citizenship to children of illegal immigrants, it would be following an international trend,” he added.

Several GOP candidates including Donald Trump, Ted Cruz, Scott Walker and Rand Paul have come out against birthright citizenship, arguing that the policy serves as a magnet for illegal immigration.

Some countries that do not grant birthright citizenship according to NumbersUSA’s 2014 list include:

Australia

Austria

Belgium

Cyprus

Czech Republic

Denmark

Finland

France

Germany

Greece

Hong Kong

Iceland

India

Iran

Iraq

Ireland

Israel

Italy

Japan

Liechtenstein

Luxembourg

Malta

Monaco

Netherlands

New Zealand

Norway

Portugal

Saudi Arabia

Singapore

Slovakia

Slovenia

South Korea

Spain

Sweden

Switzerland

Taiwan

United Kingdom