Previously it had been thought almost all women involved in child sex abuse were acting under the influence of a male partner. A Home Office spokeswoman said: "This rise is partly due to the changing climate and more children feeling able to come forward about these sorts of crimes."
There are 20 women in prison for the sexual abuse of children. Figures show 38 women were prosecuted for such offences in 1996, although it is believed many cases are dropped because of a widespread reluctance to accept that such crimes occur.
In July an English teacher, Lucy Hayward, 30, was jailed for two years after having sex with a 15-year-old boy she had invited to her house and "plied with drugs".
Tina Purser, a nurse, was given two years' probation in 1996 after admitting she had sex with a boy of 12 when she was 26. Purser, who plied him with sweets and money, pursued the affair for two years. The family of the boy claimed he had been "raped of his innocence". But most cases of female sex abuse never come to court.
Michelle Elliott, of the charity Kidscape, which did the research, said many attackers were mothers, step-mothers and grandmothers. "Because of this the victims are some of the most damaged people that I have ever seen. They experience lifelong difficulties with relationships." It was almost unheard of for children to be snatched off the street by a female abuser and most stranger attacks were usually by baby-sitters or teachers. "These cases are often wrongfully described as `seduction' when the children concerned may be only 12 or 13."
The Prison Service project will be based at Styal women's prison in Cheshire and is being prepared by specialists including Jackie Saradyn, a consultant forensic clinical psychologist at Highroyds Psychiatric Hospital, Chester.
She said: "The Prison Service has a core programme for males, but nothing for females - the main difference between the two is that women usually don't go through the court system, because they are rarely prosecuted."
Linda Jones, head of the Prison Service's Women's Policy Group, said: "Clearly, the problem of women abusing children is nowhere near as serious as male abuse but if it isn't addressed then it could be a risk to children.
"We are recognising the problem and this is all part of a new drive to develop more rehabilitative regimes generally."
It is anticipated that the project will be run on similar lines to the sex offender treatment programme operating in 25 male prisons around the country and using "cognitive-behavioural" treatments to get paedophiles to accept what they have done and challenge their thinking.
Sheila Brubaston, of Styal's probation department, said: "The programme will enable women firstly to accept that they have sexually abused a child, look at the triggers for their behaviour, and help develop empathy with the victim. Basically, it's about child protection but it's also looking at the woman as a victim herself."
About 70 per cent of male sex offenders were abused as children, research has shown, although the majority of those abused do not go on to abuse children themselves.
Four different studies have placed the proportion of female paedophiles who were abused at between 50 and 100 per cent.
The architects of Styal's new programme are hopeful that female offenders will be more open and responsive to therapy than men.
Ms Saradyn said: "Women have a sort of double guilt, because they have not only abused a child but have also breached the sense of how society sees women, which will hopefully enable them to take responsibility for their behaviour earlier."Reuse content