Your son would be eligable to hold a Canadian passport and represent Canada in the Olympics (example used before for Cain), even if he was born and raised in England.. he would have as much right as anybody from Canada to be Canadian.
I can't imagine any scenario where my son would not be English - because i am English, Cain's father is Mexican and Cain has every right to be Mexican - he is Mexican, ontop of this to my knowledge he has never said anything bad about the US.
I really don't get this argument, these things are personal choice.
Its really not a personal choice though. That concept in general is what offends me. You are born in a country you lived there were a part of that society, when you were sick you went to there hospitals, when your family was unemployed you got the money from there government, you worked there and payed taxes there and enjoyed all the freedoms that are provided by that country.
He may not say anything bad about the US but to me just to prance around with another countries flag is insulting IMO because in a sense I see it as paying tribute to a country but not the one that provided you with your quality of life.
This is kinda the issue many Canadians have with Quebec because many don't pay tribute to Canada but merely Quebec despite the fact that they take advantage of all the things being Candian provides them with.