The government has defended plans to monitor children as young as three for potential criminal behaviour.
Children with difficulties would be identified
Children's minister Beverley Hughes said it was important to identify problems as early as possible.
However, she added: "There is a balance to be struck between intervening early and labelling children prematurely."
It is expected that professionals could look for signs such as difficulties respecting boundaries or responding to adults, and offer appropriate help.
"I don't think you can tell whether a three-year-old is likely to become a criminal," she told BBC Radio 4's Today programme.
"What you can begin to identify is children who are having difficulties at an early age and on the basis of that concern, make sure that parents and the child have the assistance to avoid those problems becoming any deeper."
The Home Office leaked document said children who were not "under control" by the age of three were four times more likely to be convicted of a violent offence.
It suggested parenting classes and, in the worst cases, putting children who were not "under control" into intensive foster care instead of care homes, the Sunday Times reported.
Mrs Hughes said the monitoring would be done "very sensitively".
"But I think the professionals working with children understand that very, very well," she added.
The Professional Association of Teachers, which incorporates the Professional Association of Nursery Nurses, said teachers already identify and help children with learning and social problems, but they were professional childcarers, not criminal psychologists.
General secretary Jean Gemmell said: "We would be alarmed if nursery staff were to be asked to take on some sort of Big Brother-style role on behalf of an all-controlling state.
"Trying to identify potential criminals before they've even started school seems impractical.
"We would not want to see children labelled as troublemakers before they've done anything wrong," she added.