Early on, girls begin to menstruate, which is dramatic but not obvious to their playmates. They grow taller and rounder, but underneath their makeup they are still recognizably themselves. For boys it is far more disorienting. Puberty comes later, sometimes much later, and its delay is humiliating. While the tall round girls are getting themselves up like grown women, the prepubertal boys, with their featureless, hairless bodies, are just dirty little kids who could pass for the children of the hypermature girls.