User blog comment:Percy Jackson12/The Seven/@comment-4525239-20111015093403/@comment-3146930-20111015132111

Except we dont know what the mark of Athena is or if it even requires a child of Athena to be present. And I dont mean Percy would go to Rome by himself, but Hera is only talking to him at the time. So imagine if you were going somewhere with your friends. Your parents would say something like "Call me when you get there." Just because you are traveling in a group doesnt mean you cant be singular. The prophecy also says "Wisdom's daughter," not Athena's daughter. Yes Athena is the goddess of wisdom but it could mean something else, especially if the prophecy is incomplete