Baby teeth from children who live in the radiation paths of nuclear power plants in Connecticut and New Jersey contain alarmingly high levels of radioactive matter, scientists reported this week at the World Conference on Breast Cancer in Ottawa, Canada. Emissions from the two plants travel downwind through Long Island, N.Y., which has some of the highest rates of childhood and breast cancers in the U.S. The teeth of children born in the area since 1990 show some of the highest levels of radioactive material since the early 1960s, when superpowers were testing atomic bombs.