Hi there! My grandfather was also born in Canada. He was born in 1924 in Ontario and moved to Detroit with his parents when he was very young. He fought in WWII and was offered US citizenship then, so he became one probably around 1942. My mother was born in 1955 in Washington DC, and I don't know whether they ever registered proof of her birth abroad. Would she still be able to apply for proof of citizenship or is it not worth it? I'm not sure if my grandfather gave up his Canadian citizenship at the time he became at US citizen, but would the 2009 changes nullify that, giving my mom citizenship?