jus

Previously, anyone with an Italian ancestor who lived after 17 March, 1861 - when the Kingdom of Italy was created - qualified to be a citizen under the 'jus sanguinis', or descendent blood line law.

John Skrentny, a sociology professor at the University of California, San Diego, believes that, though birthright citizenship or jus soli is common throughout the Americas, "each nation-state had its own unique road to it".

Many African nations, which historically followed jus soli under colonial-era legal systems, later abandoned it after gaining independence.

Ireland was the last country in the region to allow unrestricted jus soli.

More than 30 countries - including Canada, Mexico, Malaysia and Lesotho - practise automatic "jus soli", or "right of the soil" without restriction.