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Key messages

The term ‘harmful sexual behaviour’ (HSB) is used to describe a continuum of sexual behaviours, from inappropriate to problematic to abusive.

There is a range of common and healthy behaviours at different developmental stages. When a child or young person behaves in ways considered to be outside this range, their behaviour may be called ‘harmful’ because it is harmful to themselves or others.

There are no accurate figures on the full spectrum of HSB. However, one major UK study found that two-thirds of contact child sexual abuse was perpetrated by other children and young people.

The majority of children and young people displaying HSB do not become sexual offenders as adults.

HSB in pre-adolescent children is more likely to be at the ‘inappropriate’ or ‘problematic’ end of the continuum rather than being ‘abusive’ or ‘violent’. Young children may be ‘acting out’ abuse they have experienced themselves, or responding to other trauma and neglect.

The early teens are the peak time for the occurrence of HSB, most of which is displayed by boys. There are some gender differences, with girls tending to be younger when their HSB is identified.

Children and young people who display HSB are more likely than other young people to have a history of maltreatment and family difficulties.

Some children and young people displaying HSB have been sexually abused themselves, but most victims of sexual abuse do not go on to abuse others. It is a history of child maltreatment, rather than sexual abuse specifically, that is most strongly associated with later sexual offending.

A significant proportion of online-facilitated sex offences are committed by young people, but limited research has been carried out into young people engaging in HSB with an online element. For some young people, there may be a link between viewing online pornography and subsequent HSB.

There is also limited published research on effective interventions, particularly at the ‘problematic’ end of the HSB continuum. However, there is a general consensus that interventions need to be holistic and child-focused, and involve families. Cognitive behavioural-based, multi-systemic and adventure-based interventions have been shown to have benefits for some children.

Services should avoid stigmatising children and young people as ‘mini adult sex offenders’.

The most effective prevention education takes a ‘whole school’ approach to healthy relationships, is longer-term and involves young people in development and delivery.

What is harmful sexual behaviour?

Sexual behaviours in children and young people can be seen on a continuum ranging from ‘normal’ and developmentally appropriate, through ‘inappropriate’ and ‘problematic’, to ‘abusive’ and ‘violent’.

Continuum of sexual behaviours by children and young people 1
Normal Developmentally expected.
Socially acceptable.
Consensual, mutual, reciprocal.
Shared decision-making.
Inappropriate Single instances of inappropriate sexual behaviour.
Socially acceptable behaviour within peer group.
Context for behaviour may be inappropriate.
Generally consensual and reciprocal.
Problematic Problematic and concerning behaviours.
Developmentally unusual and socially unexpected.
No overt elements of victimization.
Consent issues may be unclear.
May lack reciprocity or equal power.
May include levels of compulsivity.
Abusive Victimising intent or outcome.
Includes misuse of power.
Coercion and force to ensure compliance.
Informed consent lacking, or not able to be freely given by victim.
May include elements of expressive violence.
Violent Physically violent sexual abuse.
Highly intrusive.
Instrumental violence which is physiologically and/or sexually arousing to the perpetrator.

Assessing what is ‘normal’ behaviour at each developmental stage is not straightforward, and needs to take the social, emotional and cognitive development of the individual child or young person into account. Put simply, however, some behaviours that are normal in young children are concerning if they continue into adolescence; other behaviours, normal in adolescence, would be worrying in younger children. Behaviour outside the normative range may be called ‘harmful’, because it is harmful to others or to the child or young person themselves. It may range from activities that are simply inappropriate in a particular context to serious sexual assault.

The extent of HSB

Accurate figures for the extent of HSB do not exist, not least because HSB covers such a broad spectrum of behaviours, most of which do not come to the attention of the authorities.

In one UK study, two-thirds of the contact sexual abuse experienced by children and young people was perpetrated by other young people, and recent figures show an increase in reports to the police alleging sexual offences committed by young people against other young people.

What is known about children and young people who display HSB?

HSB covers a wide range of behaviours, and children and young people identified with HSB are a very diverse group. It is important to avoid generalisations and consider each child as an individual. However, the research highlights some patterns by age, gender and disability.

Pre-adolescent children

While the behaviour of some pre-adolescent children may be ‘problematic’, it is intentionally abusive in only a small number of cases. In these cases, children are likely to have experienced considerable maltreatment from early in their childhoods. Many pre-adolescent children displaying HSB have been sexually abused or exposed to developmentally inappropriate sexual experiences, such as seeing pornography. They may be ‘acting out’ such experiences as a way of communicating what has happened to them. However, such behaviour can also be an indirect response to other factors in a child’s life, including other forms of trauma and neglect.


The vast majority of adolescents who display HSB are male, even taking into account the likelihood that abuse by girls is under-reported. The early teens are the peak time for the occurrence of HSB. In some cases it is an isolated incident, or is at the problematic rather than the intentionally abusive end of the continuum.

Most sexually abusive acts are perpetrated by young people who have other major difficulties in their lives such as prior experience of physical or sexual abuse or neglect, witnessing domestic violence, a lack of positive male role models, or having parents with mental health or substance abuse issues. Like other teenagers who get into trouble, they are likely to have low self-esteem, poor social skills and difficulties with anger, depression and peer relationships.

HSB may be directed towards younger children, adult women or peers. Compared with those whose HSB targets younger children, adolescents who sexually offend against their peers tend to show higher levels of general delinquency and antisocial behaviours. Some peer-on-peer abuse takes place in the context of gangs, where the perpetration of sexual violence can be coerced or become normalised.

Most victims of sexual abuse do not go on to abuse others. Although people who commit sexual offences against children are more likely than other offenders or non-offenders to have been victims of child sexual abuse, it is a history of child maltreatment – rather than sexual abuse specifically – that is most strongly associated with later sexual offending.

Most children and young people who display HSB do not go on to sexually offend as adults; if they are arrested later in life, this is likely to be for non-sexual rather than sexual offences. Those most at risk of further sexual offending are older adolescents who abuse younger children, and children and young people whose behaviours involve violence. Two other factors associated with further sexual offending are general antisocial behaviour and sexually deviant beliefs and impulses.

Children and young people with learning disabilities

Children and young people with learning disabilities are more vulnerable both to sexual abuse and to displaying problematic sexual behaviour: in one large UK study, 38% of those referred to specialist services because of HSB were assessed as having a learning disability. Such individuals may:

  • have less understanding that some sexual behaviours are not acceptable
  • receive less sex and relationship education than other young people
  • have fewer opportunities to establish acceptable sexual relationships
  • struggle with social skills generally
  • relate more easily to children younger than themselves.

Girls and young women

Most research is based on male samples, so less is known about HSB in girls and young women. However, research suggests that girls with abusive sexual behaviours have experienced higher levels of sexual victimisation (including intra-familial sexual abuse, other forms of abuse and frequent exposure to family violence) than boys. In common with their male counterparts, young women who display HSB are often reported to have difficulties in school and to have relatively high levels of learning difficulties. HSB tends to be identified at a younger age in girls than in boys, and tends to involve younger victims; it is less likely to involve penetration or coercion. Girls are less likely to be charged with an offence, in part because they and their victims tend to be younger.

HSB and the internet

Research into young people engaging in HSB with an online element is still very limited – and, given the changing context of young people’s use of social media, it is a challenge to determine what are developmentally ‘normal’ and ‘problematic’ online behaviours. For example, a 2016 UK survey found that 48% of 11–16-year-olds had viewed pornography – and among those who had done so, boys were approximately twice as likely as girls to have actively searched for it. An earlier US study found that boys were more likely than girls to view more extreme images, more often and at a younger age.

Studies have estimated that young people commit 3–15% of offences involving CSA imagery, and a similar proportion of offences involving online sexual communication with children. Some research indicates that young people who view CSA imagery may be different from those who commit other kinds of sexual offences: they may be less likely to have experienced adverse childhood experiences, and more likely to come from stable and economically advantaged family backgrounds and be achieving well educationally.

There is insufficient evidence to demonstrate that viewing CSA imagery leads to other forms of CSA, but for some young people there may be a link between viewing online pornography and subsequent behaviour. One UK study found that, among young men displaying both online-facilitated HSB and purely ‘offline’ HSB, the developmentally inappropriate use of pornography had been a trigger for offline HSB in more than half of cases.

Effective assessment of children and young people displaying HSB

There is little published research on the most appropriate ways of assessing children and young people presenting with HSB, although there is general agreement that assessments need to take account of the whole circumstances of the child and their family – including any prior experience of abuse and other behavioural issues. There are a number of tools aiming to assess the likelihood of a child’s HSB persisting or escalating, but none has been validated as a predictive measure.

There is general support for the use of holistic assessment tools to help practitioners tailor their support to children and young people. These consider both the specific risks of the young person’s behaviour and motivations and their needs and strengths at individual, family and community levels.

Effective interventions

For children displaying HSB

There is little research on specific interventions for children who display HSB, but there are indications that structured, holistic and family-oriented approaches are of value – with some evidence that cognitive behavioural therapy (CBT) programmes may be most effective over the longer term. Given that many young children displaying HSB have themselves experienced abuse, interventions identified as effective with child victims are relevant: these include developmentally appropriate behavioural or cognitive behavioural approaches which are also trauma-informed and multi-systemic, intervening with both the child and their wider family.

For young people displaying HSB

For young people who display HSB, responses derived from models developed with adult sex offenders are now widely recognised to be inappropriate. Research highlights the damaging effects of stigmatising young people as ‘mini adult sex offenders’, which may even increase the likelihood of reoffending.

There is a consensus that responses need to be proportionate to the nature and extent of the behaviour, and to the young person’s age and developmental stage; and need to consider their whole situation, not just their problem behaviour. As with younger children, this holistic approach needs to take account of the young person’s own history of abuse.

Several studies have explored the effectiveness of approaches including CBT and relapse prevention, but evaluation has been hampered by the diversity of programmes and inconsistency of practice. The limited evidence derives largely from studies of young men who have been convicted of sexual offences. There is little evidence on interventions for young women or those with learning disabilities. Nevertheless, key messages from recent research reviews are that:

  • cognitive behavioural-based interventions, multi-systemic therapy and adventure-based interventions can benefit some young people
  • approaches that include the family and their social context appear more likely to improve social and psychological wellbeing and reduce the risk of re-offending.

In recent years there has been increased interest in resilience models, which aim to mobilise young people’s strengths and reduce the risk of repeat HSB by helping them to develop positive relationships and pro-social ambitions. Although there is little evaluative evidence of such approaches, their principles are consistent with what we know from offender follow-up studies about the factors that contribute to better outcomes – these include young people having aspirations and hopes for their future, stable and enduring adult relationships, better educational achievement, and opportunities and skills to gain employment.

Interagency working

Although service provision and awareness of HSB has increased over the past 15 years, concerns remain about inconsistencies in the way children and young people are responded to across children’s services, the child protection system and the criminal justice system. Commentators have highlighted the need for joined-up processes to avoid under- or over-reaction by agencies to young people displaying HSB. A tiered approach to meeting young people’s needs has been advocated, ranging from support for parents to intensive specialist intervention. The safeguarding and support needs of young people displaying HSB need to be prioritised, and the role of the criminal justice system needs to be considered. Access to services should not depend on a young person being charged with an offence, but targeted youth justice interventions may be the most appropriate response for some young people.

Preventative approaches

There has been a growing interest in the role of preventative approaches, often in response to concerns about child sexual exploitation and peer-on-peer abuse. A number of school-based programmes have been developed to raise awareness and promote healthy relationships, by facilitating discussion about consent and providing information about support and advice. The rationale behind many of these programmes is that unhealthy attitudes and behaviours need to be addressed at an early stage, not only at an individual level but also at community and societal levels.

Evaluations of such school-based programmes have found minimal impact on young people’s behaviour, although they can build confidence, increase knowledge and change some attitudes that may legitimise harmful behaviours. The most effective approaches are longer-term and involve young people in development and delivery. They also take a whole-school approach: alongside classroom-based sessions, schools consider how they promote healthy relationships across the curriculum, in their bullying and safeguarding policies, in their pastoral support and in the information and support they provide to parents.


  1. Hackett, S. (2010) Children and young people with harmful sexual behaviours. In Barter, C. and Berridge, D. (eds.) Children Behaving Badly? Peer Violence between Children and Young People. Chichester: Wiley-Blackwell.