There are twelve ways to lose your Canadian citizenship.
1) As a minor child ones father took out citizenship in another country.
2) You were a foreign-born Canadian, and on your 24th birthday you weren't domiciled in Canada .
3) You were a War Bride who never became naturalized.
4) You were a War-Bride child who never was naturalized.
5) In certain circumstances, you were a second-generation born abroad Canadian and you didn't reaffirm your citizenship by your 28th birthday.
6) You were a border-baby, meaning you were born in the U.S. (mainly because the nearest hospital was in the States rather than Canada ), and you were never properly registered. People from Quebec were particularly affected.
7) In certain circumstances, your connection to Canada came through a women rather than a man. This mainly affected foreign born, born in-wedlock children to Canadian mothers and foreign fathers. In 1997 the Canadian Supreme Court ruled CIC was guilty of gender discrimination, thus granting citizenship to this group on application. However, in 2004 CIC decided to ignore the Supreme Court's ruling, thus Canada went back to blatantly discriminating against women.
8) You were born out of wedlock.
9) You were born to a Canadian serviceman outside of Canada, commonly referred to as military Brats.
10) You are a woman who married a non-Canadian prior to 1947.
11) You are a child of a woman who married a non-Canadian prior to 1947. (It doesn't matter that you've spent your whole life in Canada or were born in Canada!)
12) You took out citizenship in another country prior to 1977.
Do you fit into one of the above groups?
In fact close to one-million people do. That's quite a number, being that Canada is a country of just over 33-million persons.