People in England are being asked for their views on what should be done to make children's lives better.
Gordon Brown wants more focus on children
The consultation is being launched by Prime Minister Gordon Brown and the first Children's Secretary, Ed Balls.
The government says it will use the answers to help draw up a 10-year plan for children's services.
People are being asked for their views on services as well as the roles of parents and community and what to do to keep children out of trouble.
The government was stung by a controversial report earlier this year from Unicef, which put the UK at the bottom of a league table of children's well-being among 21 industrialised nations.
It argued that the report was based on out-of-date information and that its polices had helped to improve children's welfare.
But when Gordon Brown became prime minister he changed the education department to become the department for children, schools and families, to put a greater focus on children.
All services and policy relating to children were brought under the same department - schools and standards, children's health, sport, youth justice and children and families in general.
'Out of trouble'
Children's Secretary Ed Balls announced the 10-year plan in the Commons after he was appointed, saying it would set out the long term goals for the new department.
The consultation - open to the general public and professionals alike - starts with the prime minister taking part in what is called a "citizens' jury".
A group will discuss a range of questions such as "How can we keep young people out of trouble?" and "What are your best experiences of support for children, young people and their families?".
It is such questions which will appear on the government's consultation website, although officials say people will be able to make any point they like.
Speaking on the Today programme on BBC Radio Four, Mr Balls said the government had taken on an "under-performing" education system which was "letting down children" but that it intended to make it world class.
The aim was give children at state schools the kind of resources available to those at independent schools, he said.
He also wanted to see the "stubborn pocket" of children, some 20% who were not reaching the expected standards in maths and English, be helped to achieve.
"The only way to do this is to start really early - it's about parents reading to their children in the early months of their lives. It's about making sure that from the very beginning we are tracking the progress of individual children."