Parents of teenage children sometimes ask me: “How could my son/daughter do such a stupid thing? Where is his/her head?” Psychologists, neurologists and pediatricians are starting to explain the basis underlying the sometimes weird and inexplicable behavior of some adolescent-age youngsters. The idea is that two interacting neurological systems are responsible for the passage from childhood to adolescence. In recent decades the balance between the two systems has changed so revolutionizing adolescence. The first is a system that controls emotions and is very sensitive to the biological changes of puberty. This system transforms a boy of ten into a restless, exuberant and emotional youngster. In this stage teenagers run various risks to obtain the admiration and respect of their same-age mates. They are careless and take risks not because they don’t understand the risks but because they overestimate the rewards. The football championship or first love, have an incomparable intensity. The second system starts to develop before puberty and is controlled by the brain prefrontal area. It guides decision taking and may inhibit some decisions. This is a control system and it improves through experience by correcting previous not optimal decisions. Once puberty begins it exercises a control on this bubbling energy youngsters have. Until a few decades ago the two systems were well in line. Children developed those abilities that would be useful in adult age. Peasants, hunters, cooks slowly learned with the help of the control system the skills they would need in life. As puberty set in, they had a background that protected them from making dumb mistakes. There was a sort of coordination between skills that had been developed and the freedoms that puberty pushed for. So even if puberty and control system have quite different agendas there were points of contact. Today the relationship between the two systems has changed mainly for biological reasons. Puberty begins earlier (partly because youngsters are less active and eat more. This means that the emotional changes of puberty begin earlier and take up areas that once would have belonged to the control system. Not only, but the experiences these youngsters have are mainly school related. History, Philosophy, and Literature test the control system mainly in academic situations. Studying Chemistry is obviously important but it does not prevent us from burning the pie we so wished to eat. The control system is overwhelmed by the early development of the emotional system connected to puberty. The car was sold with only the accelerator. Brakes and steering wheel will come later.