The insanity crept up on us slowly; we just wanted what was best for our kids. We bought macrobiotic cupcakes and hypoallergenic socks, hired tutors to correct a 5-year-old's "pencil-holding deficiency," hooked up broadband connections in the treehouse but took down the swing set after the second skinned knee. We hovered over every school, playground and practice field — "helicopter parents," teachers christened us, a phenomenon that spread to parents of all ages, races and regions. Stores began marketing stove-knob covers and "Kinderkords" (also known as leashes; they allow "three full feet of freedom for both you and your child")...