Back when I took calculus in high school, the instructor asked for a show of hands for first-borns. All hands but one went up--well above 80%. I've wondered w

Back when I took calculus in high school, the instructor asked for a show of hands for first-borns. All hands but one went up--well above 80%. I've wondered why that was so ever since. Why weren't middle and younger children pushing themselves to get into the "advanced" math classes?