Swedish nationality law determines entitlement to Swedish citizenship. Citizenship of Sweden is based primarily on the principle of jus sanguinis. In other words, citizenship is conferred primarily by birth to a Swedish parent, irrespective of place of birth. In general, children born in Sweden to foreign parents do not acquire Swedish citizenship at birth, although if they remain resident in Sweden they may become citizens later on. Swedish law was significantly amended with effect from 1 July 2001 and from that date, dual citizenship is permitted without restriction. Birth A child born after 1 April 2015 acquires Swedish citizenship automatically if: one of the parents is a Swedish citizen at the time of the child's birth a deceased parent of the child was a Swedish citizen upon their death A child born before 1 April 2015 acquired Swedish citizenship at birth if: the child's father was a Swedish citizen and was married to the child's mother; or, the child's father was a Swedish citizen, the child was born out of wedlock, and the child was born in Sweden; or, the child's mother was a Swedish citizen, and the child was born on or after 1 July 1979. For example, a child born to a Swedish father and a non-Swedish mother will not be Swedish if either: their parents are not married to each other or if their parents were not married when the child was conceived and they were born outside of Sweden, unless the father sends notification to an embassy or consulate with the child's passport, birth certificate, proof of his own citizenship at the time of the birth, and a certificate of paternity. A child who is born abroad and whose father is a Swedish citizen (not married to the child's mother, and the mother is not Swedish) will acquire Swedish citizenship when their parents get married, provided the child is aged under 18. Older legislation The law that governed the transmission of citizenship before the Citizenship Act of 2001 was the Citizenship Act of 1894 (law number 71, 1 October 1894), with intervening reforms in 1924, 1950, and 1979. Adoption A child who is aged under 12 and who has been adopted by a Swedish citizen automatically receives Swedish citizenship upon adoption if the child has been adopted as the result of a decision taken in Sweden or in another Nordic Council country the child has been