well vieri was born in italy ... then his family moved to australia and then they moved back to italy. rossi was born in new jersey and lived there until he left at 12 to join parma's academy. so i wouldn't associate vieri with a snake like rossi who if italy didn't think was good enough would have been proudly claiming his love for the us national team.
even though i don't like that subotic didn't pick the US, who helped his refugee family in their time of need after germany told them to kick rocks ... he wasn't born here and ungratefulness is not that big of a deal.
oh and your son may have those options, but if he turned out to be really good it would be pretty shitty for him to turn his back on the country where he was born AND RAISED. with immigrant countries like america and austrailia i always point out that people immigrated there for a reason. if the motherland was so awesome you would have been born there.