There are over 86, 000 people in jails, young offender institutions and immigration removal centres.
McKenzie-Jackson and Tulloch will both serve half their sentences at young offender institutions.
Riliwanu Balogan was found hanged at Glen Parva Young Offender's Institute in Leicester a day after his 21st birthday in 2011.
Their son John was jailed for four years, while their other son James was sentenced to three years in a young offender institution.
He offers the analogy of a conveyor belt, on which the individual passes through successive stages: neglected child, disruptive pupil, anti-social teenager, young offender, hardened criminal.
In Swansea, police and social services, together with health and council staff, decide whether it is more appropriate for a young offender to go through the court system and end up with a criminal record or whether they could benefit from a "second chance".
BBC: Youth and child crime rates fall in Wales, YOT figures show
Children's services manager Denise Moultrie said she believed many professionals were reluctant to label a young person as a sex offender.
But she doesn't believe that the shy, introverted young man should carry the sex offender label for the next 15 years.
They have described him as a predatory sex offender and believe he may have abused many people - including young girls - over a 40-year period.
They have described him as a predatory sex offender and believe he may have sexually abused many people, including young girls, over a 40-year period, sometimes on BBC premises.
Gilbert said police thought they'd caught a break in 2004 when convicted sex offender Edward Dukette, who served time in a Florida prison for raping and nearly killing a young girl, unexpectedly came forward to police claiming he had key information about Kathy Gloddy's murder.
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