New technology could leave children lonely, according to the Children's Commissioner for England.
Maggie Atkinson questioned if activities and video games left children with "nobody close to them".
She also said parents needed to allow young people to take risks, in a speech organised by the children's charity Barnardo's in London on Thursday.
The commissioner asked if pupils were in danger of becoming too regimented by school life.
Ms Atkinson suggested that after-school activities, new technology and video games could alienate young people.
"Are we meant to provide them with an activity to fill very waking hour and a room full of technology, but nobody close to them who has the time either to talk to them, or to fathom life out with them?" she said.
She also asked whether children were becoming "little bundles trained in a mechanistic model of education" as opposed to rounded human beings.
Ms Atkinson compared her childhood, 45 years ago, to children's experiences today, claiming "too many" modern children did not leave their back gardens, whereas she used to play a mile from home unsupervised.
Over-protective parents, she said, would do better to teach "independence, choice-making and resilience" in their children.
She said: "We need to encourage parents to find a balance between keeping them safe and keeping them confined."
Ms Atkinson said that tough discussions needed to take place on youth justice, an area in which she claimed the United Nations constantly criticised England's approach.
She said: "Numbers in the system have started to fall. They have a long way further to go."
She also questioned attitudes to young people and promised to challenge "negative and false stereotypes of an entire generation".
"Are they here to be disciplined so they unquestioningly comply, know their place, do as they are told - or to be questing and questioning but positive citizens from an early age?"
The Children's Commissioner acknowledged that many young people were "deeply offended" by being labelled as troublemakers.