In a new opinion piece in the Lancet Child & Adolescent Health journal, a group of seven academics make a case for redefining adolescence from ages 10-19 to 10-24. It is a redefinition, they say, that reflects an evolving society where puberty hits earlier, bodies develop into the 20s, and where young people leave home, get married, have children and gain economic independence later than ever. Lead author Prof Susan Sawyer, director of the centre for adolescent health at the Royal Children's Hospital in Melbourne, writes: "Although many adult legal privileges start at age 18 years, the adoption of adult roles and responsibilities generally occurs later." @LancetChildAdol Viewpoint: The age of #adolescence—an extended and more inclusive definition to framing better laws, social policies, and service systems for this life phase @LancetYouth https://t.co/KKpJeGjv4W pic.twitter.com/RfVRIDYovk — The Lancet (@TheLancet) January 18, 2018 
 
 “Good information systems are an important step towards making adolescents and their health more visible to policy makers, researchers, donors and development partners,” she wrote in 2012. That is how Statistics Canada defines young years, often further describing the 15-19 years as “adolescents” and the 20-24 years as “young adults.” 
 
 Some academics contest the Lancet piece, including sociologist Jan Macvarish from the University of Kent, who tweeted that “science really can't tell us how to live our lives and raise our children and what adulthood means.” 
 
 But Sawyer is intent on a redefinition.
– Good news for young people tired of being told to grow up: A team of academics writing in the Lancet wants to expand the period in life we think of as adolescence by five years, CTV News reports. "The transition period from childhood to adulthood now occupies a greater portion of the life course than ever before," the team writes in an article published Wednesday. They argue for delaying the end of adolescence, which starts at 10 years old, from 19 years old to 24 years old. "Age definitions are always arbitrary, [but] our current definition of adolescence is overly restricted," the BBC quotes lead author Susan Sawyer as saying. The team argues there are physiological and sociological reasons for expanding adolescence. Scientists now know the brain continues to develop after the age of 20. And young people are moving away from their parents, getting married, and having their own children later than at any other point in history. In Britain, people are getting married nearly eight years later than they were in 1973. The team says adolescence should be redefined for the good of the 1.8 billion people between ages 10 and 24 on the planet. “An expanded and more inclusive definition of adolescence is essential for developmentally appropriate framing of laws, social policies, and service systems,” the article states. However, sociologist Jan Macvarish warns we could end up infantilizing young people. "Society should maintain the highest possible expectations of the next generation," she says.