Plans to offer more drug treatments to sex offenders to try to stop them committing more crimes are being announced by the Home Office.
The treatment involving libido-reducing drugs or anti-depressants would be given on a voluntary basis.
Parents will also be able to ask for checks on whether new partners or people dealing with their children are known sex offenders.
But the Home Office says details will not be available to the wider public.
Convicted paedophiles might also be subjected to lie detector tests if there is a suspicion they are targeting children.
Prime Minister Tony Blair told MPs during Commons questions that allowing parents to find out if people in close contact with their children were sex offenders was "a sensible, worthwhile step forward".
And Home Secretary John Reid told BBC News: "Prison and punishment should take place when people are guilty of child offences but in addition to that we need, after that, to treat them, to supervise them and to share information."
Some of the most persistent sex offenders are already offered drug treatment, but the Home Office says this provision could be increased.
Mr Reid said sex offenders would be offered drug treatment on a voluntary basis alongside other measures, including supervision.
"The evidence suggests that it's far more effective and only really effective if someone is getting this treatment voluntarily, as part of a treatment course."
He said allowing everyone to have access to information about sex offenders - a measure known as Megan's or Sarah's Law - could drive paedophiles underground, so he had decided on a "middle way".
This allows "vulnerable people, especially young single parents with young families" to find out whether a new partner or other adult who came into contact with their children was a sex offender.
'No honour'
Dr Donald Findlater, director of research and development at the child protection charity the Lucy Faithfull Foundation, said: "I think we have this notion that all sex offenders want to do bad things all the time. Some of them are desperately struggling with what's going on in their lives, and want help to be stopped.
"Some of them have been very enthusiastic about participating in lie detector tests, and indeed would happily take pills if that will help."
Sara Payne, whose daughter Sarah was murdered by paedophile Roy Whiting seven years ago, told the BBC that drug treatment should be compulsory.
"You're placing an honour based system on people that have already shown they have absolutely no honour.
"These are people that rape, molest our children, take photographs of what they're doing.
"They've already shown that they are the nastiest, I think the nastiest, people in the world because of what they do to children."
The review is expected to recommend that parents, for the first time, could have access to information on convicted paedophiles.
For example, mothers could request a police check if they have concerns about a new boyfriend.
At the moment, employers can request a Criminal Records Bureau (CRB) check if a potential employee is going to work with children, while private citizens cannot.
Three pilot areas are expected to be set up.
Widespread access to details about sex offenders, as seen in the US, has been ruled out by the Home Office.
The US law, known as Megan's Law, named after Megan Kanka, seven, who was killed by a convicted sex offender, gives parents access to names and addresses of known paedophiles.
A campaign to launch a "Sarah's Law" - a UK version of the legislation - was launched after Sarah Payne's murder in 2000.