Understanding age-inappropriate or harmful sexual behaviour in children and young people, and how to assess and respond using evidence-based frameworks.
Harmful Sexual Behaviour is sexual behaviour displayed by children and young people that is developmentally inappropriate, harmful to themselves or others, or potentially abusive.
Harmful sexual behaviour (HSB) refers to sexual behaviours in children and young people that are developmentally inappropriate, may be harmful to themselves or others, and may indicate abuse or trauma. Not all sexual behaviour in children is harmful — Brook's Traffic Light Tool provides a widely used framework for distinguishing between green (healthy), amber (concerning), and red (harmful) behaviours based on a child's age and developmental stage.
HSB exists on a spectrum. Green behaviours are healthy and age-appropriate (such as curiosity about bodies in young children). Amber behaviours are outside what is developmentally expected and require a closer look. Red behaviours are harmful, exploitative, or coercive and require an immediate safeguarding response. Children displaying HSB may themselves have experienced sexual abuse or been exposed to sexual content. Professional assessment is required before concluding that behaviour is harmful.
In your child's behaviour
On their device
Use Brook's Traffic Light Tool
Brook's Traffic Light Tool is a widely used and evidence-based framework for understanding sexual development and identifying concerning behaviours. All staff working with children should be familiar with it.
Provide age-appropriate Relationships and Sex Education
RSE that is developmentally appropriate, accurate, and delivered well helps children understand consent, healthy relationships, and their right to bodily autonomy. This is a primary prevention measure for HSB.
Refer amber and red behaviours for professional assessment
Do not attempt to assess HSB without specialist support. Amber and red behaviours should be referred to your DSL and may require input from specialist services such as CAMHS or a specialist HSB assessment team.
In immediate danger: call 999. For non-emergency police matters, call 101.
Concerned about a child but it's not an emergency? NSPCC helpline 0808 800 5000. Childline for young people 0800 1111.
This is practical educational content to support families. For case-specific concerns about a child's safety, contact the NSPCC helpline on 0808 800 5000 or your local safeguarding team.
Myth: Harmful sexual behaviour is just a child being naughty or over-curious — it's nothing to take seriously.
Fact: Not all sexual behaviour in children is harmful — plenty of it is normal curiosity. But when behaviour becomes frequent, coercive, involves a big age or power gap, or goes beyond what's expected for a child's age, it moves further along what researchers call the Hackett continuum (used by the NSPCC), from 'normal' towards 'inappropriate', 'problematic', 'abusive' or 'violent' — and deserves a closer, calm look rather than being waved away.
Myth: A child who shows harmful sexual behaviour is destined to become an abuser as an adult.
Fact: This isn't what the evidence shows. NSPCC research finds that the majority of children and young people who display harmful sexual behaviour do not go on to become sexual offenders as adults. HSB in a child often signals something else going on — such as exposure to inappropriate content, trauma, or abuse the child has experienced themselves — and most children respond well to the right support and intervention, arranged through your school's DSL or a specialist HSB assessment pathway.
Myth: Only teenagers display harmful sexual behaviour — it doesn't happen in younger children.
Fact: Sexual development starts young, and so does the need to tell healthy curiosity apart from something more concerning. Tools such as Brook's Sexual Behaviours Traffic Light Tool are designed for use with children and young people up to 18, including under-5s, precisely because what counts as typical ('green light') behaviour looks very different in a four-year-old than in a fourteen-year-old. Judging behaviour against a child's actual age and stage — rather than assuming a young age rules HSB out — is the safer approach.
Some curiosity about bodies and gentle self-touching is a normal part of development at this age. Teach your child the correct names for body parts, simple rules about privacy (for example, that some parts of the body are private), and that they can always tell you if something feels confusing or uncomfortable. If behaviour is frequent, involves another child in a way that seems forceful, or shows knowledge beyond what a young child would typically have, it's worth talking to your health visitor, GP, or nursery.
Exploratory play between children of a similar age (like 'playing doctors') is common and usually not a cause for concern. What matters is context: behaviour that's secretive, repeated, involves pressure, or involves a much older child is worth a calm conversation and a note to your child's school. Keep reinforcing body boundaries and that no one — child or adult — should ask them to keep a secret that makes them uncomfortable.
As children approach puberty at different rates, ongoing, age-appropriate conversations about privacy, consent and respecting other people's bodies help set expectations early. If you notice behaviour that feels coercive, persistent, or involves a significant age or power difference, raise it with your child's school (who can refer for assessment via routes such as CAMHS) rather than trying to judge it alone — a calm, non-blaming response works best for every child involved.
This is often when children start navigating relationships, curiosity about sex, and online contact with peers. Talk openly about consent, that pressuring someone — online or in person — is never acceptable, and that sharing sexual images of another child is a serious matter, not harmless fun. If you're concerned about a child's behaviour towards others, contact your school's Designated Safeguarding Lead, who can arrange a proportionate, professional assessment rather than you needing to judge how serious it is alone.
Was this page helpful?
Get practical child safety updates in your inbox. No spam.