Nationality laws vary greatly around the globe.

In Greece, for example, some children face insecurity and confusion because they are not Greek citizens, despite being born in and living in the country. In Japan, the government may pass a law granting 20,000 mixed race children Japanese citizenship.

When a child is born, he or she can gain a nationality in a variety of ways – from the place of birth or from parents’ nationalities or ethnicities; sometimes automatically and other times requiring an application process.

Standard basis for citizenship:
Jus soli — birthright — a rule that the citizenship of a child is determined by the place of its birth
Jus sanguinis — blood right — a rule that a child’s citizenship is determined by its parents’ citizenship

The chart below details the foreign populations in world countries, residency requirements for naturalization (excluding special factors such as marriage to a national) and types of citizenship.

Data is from 2005, the latest available date for comprehensive comparative information. For more detailed information on citizenship laws and requirements in a particular country, visit that country’s Web site.

	642,000 15.9% of population *	Residence for 1,350 days of past 5 years	Eliminated birthright  citizenship in 2006
	1.2 million 15.1% of population 40.9% are nationals	10 years continuous residence	Blood right
	585,000 14.1% of population 45.2% are nationals	3 years residence	Eliminated automatic birthright citizenship in 2004
	38.36 million 12.9% of population 46.4% are nationals	Legal residency for 5 years	Birthright
	10.14 million 12.3% of population	At least 8 years  residence	Blood right
	6.47 million 10.7% of population 53.1% are nationals	5 years residence	Blood right; delayed birthright (can acquire citizenship on request)
	5.41 million 9.1% of population	5 years residence	Many types of  citizenship (vary)
	974,000 8.8% of population 41.5% are nationals	10 of last 12 years	Blood right; birthright if  no other nationality  acquired
	2.52 million 4.3% of population 47.5% are nationals	10 years residence	Blood right; birthright if no other nationality acquired
	168,000 2.7% of population	3 years residence	Birthright
	1.11 million 2.3% of population	4 of 8 last years	Blood right
	124,000 2.3% of population	5 years residence	Blood right
	2.05 million 1.6% of population	5 years of residence	Blood right
	644,000 0.6% of population	5 years residence	Birthright; recognizes  dual nationality
	596,000 0% of population	Settlement in China	Blood right

*When data on foreign-born nationals is blank, the information is not available.
Sources: United Nations, NationMaster. Photos courtesy of Flickr users under a Creative Commons license.