Canadian citizenship by descent
Any person born outside Canada from 15 February 1977, who has a Canadian parent at the time of birth, is automatically a Canadian citizen by descent.
If the Canadian parent is also Canadian by descent and the other parent is not born or naturalized in Canada, then Canadian citizenship will be lost on that person’s 28th birthday unless the person successfully applies to retain Canadian citizenship.
Those born outside Canada between 1 January 1947 and 15 February 1977 are generally not Canadian citizens unless their birth was registered with the Canadian government before they were two years of age (and neither they nor their responsible parent subsequently lost Canadian citizenship by becoming citizens of another country before 1977) OR they applied for Canadian citizenship by descent before 14 August 2004. Applications for citizenship by descent fell into two categories: 1) delayed registration of birth abroad, which, when granted, made the person a citizen from birth (as if the birth had been registered with the Canadian government within two years as required by the 1947 Citizenship Act), and 2) a facilitated grant, in cases where the Canadian parent was the mother, not the father. The latter was not retroactive, so does not make children of the grantee born before the grant, Canadian citizens.
One class of Canadian citizens by descent who can still claim citizenship are those whose births were registered as required by the 1947 Act, but who then lost their Canadian citizenship when their responsible parent (normally the father) became a naturalized citizen of another country. In 2005, the Canadian Parliament passed a law allowing such persons who lost citizenship as minors to apply to resume Canadian citizenship without a residency or background-check requirement.