Children learn a whole raft of skills in the first seven or eight years of life by closely imitating their parents and teachers. But for children to grow up as clones at a time of rapid cultural and economic environmental change would be nothing short of disastrous. We now know that children need the struggle of adolescence to put away those childish behaviours. Recent research in cognitive science and neurobiology makes it obvious that apprenticeship--a form of intellectual weaning whereby the more skillful and thoughtful the apprentice became, the less he or she would depend on the teacher--was a more culturally appropriate response to the neurological changes in the adolescent brain than our current school systems provide. To waste adolescence is to deny future generations the strength they will need to respond to the serious problems facing our civilization and our planet.