I take issue with your calculation. Children of typically over-the-hill Congressmen are many times more likely to be in the age range appropriate for military service than any other randomly chosen American. To expect the children of Congressmen to be represented as many as the whole American population, which includes people we wouldn't consider fit for military service (those under the age of 18 or over, say 35) is just silly. Try 60 seconds of intellectual effort next time.