Today's teenagers grow up more . Researchers looked at 8 million  over the  40 years. Today's teens are  responsible  teenagers from the 70s, 80s and . Today's 18-year- are like 15-year-olds used to be. Teenagers  take  risks than  did before.
Today's teenagers take  to do  their parents did, like , working, driving, and renting their  room. A professor said they have a, " life strategy". One  for this is many teenagers live in the  and not the " world". Another reason is parents do too  things for  children.