Harmful sexual behaviour includes:

  • using sexually explicit words and phrases
  • inappropriate touching
  • using sexual violence or threats
  • full penetrative sex with other children or adults.

Children and young people who develop harmful sexual behaviour harm themselves and others.

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Sexual behaviour between children is also considered harmful if one of the children is much older – particularly if there is more than two years’ difference in age or if one of the children is pre-pubescent and the other isn’t (Davies, 2012).

However, a younger child can abuse an older child, particularly if they have power over them – for example, if the older child is disabled (Rich, 2011).

If you're not sure whether a sexual behaviour is harmful find out about the signs, symptoms and effects of harmful sexual behaviour.

Why children develop harmful sexual behaviour 

Children and young people who develop harmful sexual behaviour have usually experienced abuse and neglect themselves (Hackett et al, 2013; Hawkes 2009; McCartan et al, 2011).

A study by Hackett et al (2013) of children and young people with harmful sexual behaviour suggests that two-thirds had experienced some kind of abuse or trauma such as physical abuse, emotional abuse, sexual abuse, severe neglect, parental rejection, family breakdown, domestic violence, and parental drug and alcohol abuse. Around half of them had experienced sexual abuse.

Research by Hawkes (2009) into the family histories of sexually abusive boys found:

"[C]hildren had grown up in an environment where their physical or verbal expressions of distress or arousal were not understood, but rather met with angry or fearful responses from their caregivers. Wilful or unconscious ignoring, misunderstanding or repressing of the children’s needs were also recurring themes. Even developmentally normal sexual behaviour by the boys was not understood by caregivers, who tended to react as though the child was a sexual threat or in some other way a sexual peer. The child’s sexual needs were not recognised and in the most extreme cases they appeared to create a pseudo-adult sexual persona to meet the expectations of caregivers."

Research by Masson et al (2015) into the family histories of sexually abusive girls found:

"[G]irls and female adolescents with abusive sexual behaviours come from particularly chaotic and dysfunctional family backgrounds, with higher levels of sexual victimisation than males, higher levels of other forms of abuse, frequent exposure to family violence and often very problematic relationships with parents. Compared to the males in our sample, the young females were likely to be referred at a younger age, they were much less likely to have any criminal convictions at the point of referral, they had higher rates of sexual victimisation in their histories and they tended to have fewer victims drawn from a more narrow age range."

Children who have been sexually abused may not know that what has happened to them is wrong. This can lead to normalisation of harmful sexual behaviours towards others (Ringrose et al, 2012).

In the vast majority of cases, children abuse someone they know (Hackett et al, 2013). Children and young people who abuse their brothers or sisters may be motivated by jealousy or anger (Yates et al, 2012).

Power is an important factor in sexual abuse. Erooga and Masson (2006) built on the work of Finkelhor and Browne (1985) to explain how a child’s early powerlessness during their own abuse can lead to them needing to dominate others.

Teenagers who sexually abuse others may also be involved in other crimes (Seto and Lalumière, 2010).

They may have some similarities with non-sexual young offenders such as behavioural problems or developmental experiences but they are also likely to have a history of sexual abuse or exposure to pornography at a young age (Seto and Lalumière, 2010).

Children who sexually abuse others are likely to:

  • have poor self-regulation and coping skills
  • experience social anxiety and a sense of social inadequacy
  • have poorly internalised rules for social behaviour
  • possess a poorly developed or primitive sense of morality
  • lack secure and confident attachments to others
  • exercise limited self-control, and act out their emotional experiences through negative or otherwise inappropriate behaviour
  • have little insight into the feelings and needs of others and, indeed, their own mental states
  • place their own needs and feelings ahead of the needs and feelings of others
  • exhibit a poorly defined sense of personal boundaries
  • have developed strong and not easily corrected cognitive distortions about others, themselves, and the world they share
  • have deficits in social skills and in social competence overall” (Rich, 2011).

Society and culture have a big impact on what children think about sex and sexuality. What they see and read on television, the internet and in other media can reinforce these ideas.

Children using mobile phones and social networking sites may also come across sexually explicit or pornographic images and video.

Case studies of boys with harmful sexual behaviours have found common concerns around masculinity, gender roles and sexual identity (Durham, 2006).

Signs, symptoms and effects

Find out about the signs, symptoms and effects of harmful sexual behaviour
Spotting signs of harmful sexual behaviour

Sexual abuse

A child is sexually abused when they are forced or persuaded to take part in sexual activities. This doesn't have to be physical contact, and it can happen online.
Read more about sexual abuse


Children and young people can be groomed online or in the real world, by a stranger or by someone they know - for example a family member, friend or professional. 
Read more about grooming

Child sexual exploitation

Child sexual exploitation is a type of sexual abuse in which children are sexually exploited for money, power or status.
Read more about child sexual exploitation

Help and advice for professionals

Library catalogue

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Research and resources

Research and reports about harmful sexual behaviour, and resources for professionals.
Find research and resources

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  1. Davies, J. (2012) Working with sexually harmful behaviour. Counselling Children and Young People, March 2012: 20-23.

  2. Durham, A. (2006) Young men who have sexually abused: a case study guide. Chichester: Wiley.

  3. Erooga, M. and Masson, H. (2006) Children and young people with sexually harmful or abusive behaviours: underpinning knowledge, principles, approaches and service provision. In: Erooga, M. and Masson, H. (eds.) Children and young people who sexually abuse others: current developments and practice responses. 2nd ed. London: Routledge.

  4. Finkelhor, D. and Browne, A. (1985) The traumatic impact of child sexual abuse: a conceptualization (PDF). American Journal of Orthopsychiatry, 55(4): 530-541.

  5. Hackett, S., Phillips, J., Masson, H. and Balfe, M. (2013) Individual, family and abuse characteristics of 700 British child and adolescent sexual abusers. Child Abuse Review, 22(4): 232–245.

  6. Masson, H. et al. (2015) Developmental markers of risk or vulnerability?: young females who sexually abuse – characteristics, backgrounds, behaviours and outcomes.. (Child and family social work, Vol.20, Iss.1) pp 19-29.

  7. Ref: McCartan, F.M. et al. (2011) Child and adolescent females who present with sexually abusive behaviours: a 10-year UK prevalence study.. (Journal of sexual aggression, Vol.17, Iss.1) pp 4-14.

  8. Rich, P. (2011), Understanding, assessing and rehabilitating juvenile sexual offenders, 2nd ed, New Jersey, Wiley.

  9. Seto, M.C. and Lalumière, M.L. (2010), What is so special about male adolescent sexual offending? A review and test of explanations through meta-analysis, Psychological Bulletin, 136(4): 526-575

  10. Yates, P., Allardyce, S. and MacQueen, S. (2012) Children who display harmful sexual behaviour: assessing the risks of boys abusing at home, in the community or across both settings. Journal of Sexual Aggression, 18(1): 23-35.