There has been a marked rise in the number of young sex offenders attending for treatment at the One in Four service.
According to the organisation's annual report for 2013, almost a quarter of all offenders in its programme are young men aged between 18 and 25.
It says many of the young men began offending as adolescents by downloading child pornography, before moving on to abusing children themselves.
Launching its annual report, Executive Director of One in Four Maeve Lewis says the problem of child sex abuse has not gone away:
