BY THE time Aaron was 17, he had raped two teenage girls and was serving time in a NSW detention centre.
His background came as no surprise to forensic psychologist Timothy Keogh. As an infant, Aaron had suffered extreme physical abuse from his mother. A succession of foster carers followed.
When he was 10, his adoptive parents relinquished him after he set fire to their house and he ended up in an institution where he was sexually abused. He was first caught stealing at 11. Alcohol and drug abuse followed.
''I felt no warmth towards him. There was something disturbing about the emotionless manner in which he talked about others,'' Dr Keogh said. ''I found myself being aware of something frighteningly violent in him.''
Dr Keogh has gone where few care to tread - into the minds of children and young people who commit violent or warped sex crimes on other children.
And his journey into the dark, internal world of the juvenile sex offender has convinced him the accepted approach to them is misguided.
''Most juvenile sex offender programs are based on the premise that all sex offenders are the same and should be treated as such,'' he said. ''But there's a world of difference in how we should approach the violent teenage rapist and the teenager who molests young children.''
Dr Keogh was a director of psychological services and programs in the Juvenile Justice department for a decade in the 1990s. More recently, he made a study of 50 convicted juvenile sex offenders, average age 16.
He says a small proportion - Aaron not included - are so damaged, lacking in empathy, and likely to reoffend that society needs to be protected.
Detention and intensive community supervision are needed, as well as good assessments to identify the 8 per cent likely to be recidivists.
But for most young sex offenders the right psychological treatment, not lengthy incarceration, is the best and most cost-effective approach, he said.
''When I looked into the history of these people I realised as a society we have to take some responsibility,'' he said. ''They weren't born bad; they're often victims, and society offered them no help.''
Their background stories differed in important ways. Those, such as Aaron, who hurt their victims, had been betrayed by parents who should have protected them. Consequently, they trusted no one and treated their victims as objects.
But others, such as Paulie, an introverted 15-year-old convicted of offences against a seven-year-old boy, believed his victim wanted his affection and sexual interest. Paulie had been sexually abused by an uncle, had dysfunctional parents, remained childlike and had developed a compulsive sexual fantasy life.
Dr Keogh said the usual approach of cognitive behaviour therapy, with its focus on changing thoughts and behaviour, would not succeed in teaching Aaron or Paulie empathy or ways to control their impulses.
The boys needed an intensive, psycho-analytical approach that would help them understand their own emotional trauma and how it had caused them to act violently and sexually.
''Unless they feel understood, it's hard for them to understand how their victims feel,'' Dr Keogh said.
The therapy used needed to address the youths' specific emotional deficits and not be a one-size fits all approach.
"As repugnant as these crimes may be, we have to develop a humane response to offenders,'' he said.
''We have to do our best to restore these young lives.''
The study is published in his book The Internal World of the Juvenile Sex Offender, to be released next week.