the resource project
When Another Child or Teenager Caused the Harm:
Understanding Child-on-Child Sexual Abuse and Harmful Sexual Behaviour
Discovering that your child may have been sexually harmed by another child or teenager can be profoundly confusing.
You may be trying to understand how something like this could happen between children. You may be worried about the child who was harmed and also concerned about the child who caused the harm. If both children are part of your family, you may love them both deeply while also knowing that something serious has happened.
You do not have to decide today what this means about either child's future.
Right now, the priorities are simpler:
Stop the behaviour. Keep the children safe. Listen without interrogating. Get appropriate professional help.
Ontario's Child and Parent Resource Institute (CPRI) specifically advises parents who discover problematic sexual behaviour to remain calm, interrupt the behaviour, separate the children, ensure everyone's safety, provide comfort, speak with children separately without blaming, establish clear boundaries and seek professional support when appropriate.
What Is Child-on-Child Sexual Abuse?
The term child-on-child sexual abuse (COCSA) is commonly used to describe sexual behaviour between children or adolescents that is abusive, coercive, exploitative or harmful.
Not every sexual behaviour between children is sexual abuse.
Children can demonstrate developmentally expected curiosity about bodies and sexuality. The important task is distinguishing that from behaviour that is problematic, harmful or abusive. Ontario's CPRI Sexual Behaviours Team specifically cautions against both minimizing concerning sexual behaviour and overreacting to developmentally expected sexual exploration.
The Canadian Centre for Child Protection describes child sexual abuse as including a sexual experience between children or teenagers that is unwanted, manipulative, or involves a significant age difference. It also emphasizes that child sexual abuse does not have to involve physical contact or force.
Concerns become particularly important when there is:
force, threats, pressure, manipulation or coercion;
a significant difference in age, size, maturity, developmental ability or power;
sexual behaviour that one child does not want or cannot meaningfully understand;
secrecy, intimidation, bribery or threats;
penetration or other intrusive sexual acts;
repeated behaviour despite intervention;
pornography or sexual images being used;
online sexual behaviour, image sharing or exploitation;
distress, fear, pain or injury;
one child exercising authority or control over another.
A professional assessment can help determine what occurred and what each child needs.
Children Who Cause Sexual Harm Are Still Children
This distinction matters enormously. A child who has engaged in harmful sexual behaviour should not automatically be labelled a predator, pedophile or sex offender.
There can be many reasons children develop problematic sexual behaviours. Ontario's CPRI identifies possible contributing factors including previous victimization, exposure to family dysfunction or violence, mental-health concerns, attachment difficulties, underdeveloped social skills, and exposure to sexualized media or environments.
None of those possibilities excuses harm to another child. That said, understanding why the behaviour occurred matters if we want to prevent it from happening again.
It is also important not to automatically assume that a child who has sexually harmed another child has themselves been sexually abused. That possibility may need careful professional assessment, but it should not be presumed.
If This Has Just Happened
Your first responsibility is safety.
Separate the children and stop unsupervised contact.
You do not necessarily need to decide immediately what permanent family arrangements will look like. You do need to ensure that another incident cannot occur while professionals help determine what happened and what level of supervision is needed.
Ontario's CPRI guidance recommends stopping the behaviour, separating the children, providing comfort and establishing clear rules and boundaries. When a child has a history of harmful behaviour or poses an ongoing risk, a safety plan should be developed.
Talk to the children separately. If a child tells you what happened, listen.
You might say:
“Thank you for telling me.”
“You are not in trouble.”
“I'm going to make sure everyone is safe.”
Avoid repeatedly questioning either child or trying to conduct your own investigation. If police or child protection become involved, trained professionals may need to interview the children.
Do not force an apology or reconciliation.
The child who was harmed should not be expected to:
forgive;
accept an apology;
hug the other child;
attend family activities together;
resume a sibling relationship;
or reassure the child who caused the harm.
Those decisions can come much later, if appropriate.
Safety comes before family harmony.
When Both Children Are Yours
This may be one of the most painful situations a parent can face. You can protect the child who was harmed and continue to love and obtain help for the child who caused the harm. Those things are not mutually exclusive even though the needs of the children may temporarily conflict. One child may need distance and reassurance that the behaviour will never happen again. The other may need close supervision, assessment, treatment and clear boundaries.
That may mean changes to:
sleeping arrangements;
bedrooms and bathrooms;
changing and dressing;
babysitting;
physical play;
device and internet access;
privacy rules;
transportation;
time alone together;
contact with younger children;
family gatherings;
and supervision.
A safety plan should be specific to the children and circumstances, rather than relying on promises such as “It won't happen again.”
Ontario's CPRI has dedicated Canadian resources for developing safety plans and creating a healthy sexual environment at home for children and adolescents with problematic sexual behaviours.
Should I Call Children's Aid?
If you have reasonable grounds to suspect that a child may be in need of protection, Ontario law requires concerns falling within the statutory reporting provisions to be reported directly to a Children's Aid Society.
Importantly, Ontario's Child, Youth and Family Services Act expressly contemplates sexual abuse by “another person” where the person responsible for the child's care knows or should know of the possibility of sexual abuse or exploitation and fails to protect the child. Ontario also requires immediate reporting of specified reasonable suspicions that a child is in need of protection.
If you're unsure whether what happened meets the threshold for child protection involvement, you can contact your local Children's Aid Society and describe the situation. CAS's role is child safety—not simply determining whether someone should be punished. Ontario's Child Protection Standards require CAS to assess referrals, determine the appropriate response and, when an investigation occurs, assess safety and risk.
What About Police?
Some child-on-child sexual behaviour may constitute a criminal offence. If a child may have been sexually assaulted, coerced, threatened, exploited, photographed or otherwise subjected to potentially criminal sexual behaviour, contact police for guidance.
There is an important age distinction in Canada:
Children under 12 cannot be held criminally responsible in Canada.
That does not mean harmful behaviour by a child under 12 should be ignored. It means the response is primarily about protection, assessment, treatment, supervision and prevention rather than criminal prosecution. Statistics Canada's police data likewise exclude children under 12 from accused-person statistics because they cannot be held criminally responsible.
For youth aged 12 to 17, Canada's youth criminal justice system may apply.
Police and CAS may also work together. Ontario's Child Protection Standards specifically require protocols between Children's Aid Societies and police when a criminal offence against a child is alleged.
Both Children May Need Professional Support
Do not assume that putting the children in therapy together is the answer. Their needs are different.
The child who experienced the harm may need trauma-informed assessment and therapy focused on safety, choice, trust, shame, fear and recovery. The child who caused the harm may need a specialized assessment of sexual behaviour to understand what happened, what contributed to the behaviour, their developmental needs and what is required to prevent recurrence. Parents and caregivers often need support too.
A Child & Youth Advocacy Centre can be particularly helpful because these centres coordinate professionals involved in child abuse cases. Boost Child & Youth Advocacy Centre, for example, works collaboratively with police, child protection, medical and mental-health professionals and provides support to children, youth and families following abuse.
Ontario CPRI Sexual Behaviours resources also maintains a dedicated Sexual Behaviours Team resource collection for children and youth up to age 18, including guidance for parents, safety planning, adolescent sexual behaviours, developmental disabilities and creating a healthy sexual environment at home.
How Common Is COCSA?
In police-reported online child sexual exploitation incidents in 2024, approximately 38% of accused persons were youth aged 12–17. Among youth accused of online sexual offences against children, 91% knew the victim. Their most frequently recorded relationships with victims were casual acquaintance (30%), intimate partner (30%) and friend (26%).
Statistics Canada also found that the median age of people accused of non-consensual distribution of intimate images was 14 in 2024.
Those numbers should not be presented as saying “38% of child sexual abuse is COCSA.” They measure a specific category of police-reported online offences, not all child sexual abuse.
For the Resource Project, I would actually say:
We do not have a reliable Canadian statistic that tells us exactly how common child-on-child sexual abuse is. What Canadian data does tell us is that children and adolescents account for a meaningful proportion of accused persons in some forms of sexual harm against other young people. Most child sexual abuse never comes to the attention of police or child welfare, official statistics cannot tell us the true prevalence, which makes quantifying COCSA very difficult.
What Happens to the Family From Here?
There is no single answer.
Some children may eventually be able to safely live together again. Others may require prolonged supervision or separation. Some sibling relationships recover. Others change permanently.
The goal should not be to restore the family to exactly what it looked like before.
The goal is to create a family environment in which:
the child who experienced harm feels safe and believed;
the child who caused harm receives appropriate assessment, boundaries and help;
other children are protected;
and adults take responsibility for managing safety so children do not have to.
Parents should not be expected to figure this out alone.
Today's Next Step
If you have just learned that one child may have sexually harmed another:
Make sure the children are safe and separated from unsupervised contact.
Listen without conducting your own investigation.
Contact Children's Aid and/or police when there is a child-protection or potential criminal concern.
Ask for professionals experienced specifically in problematic or harmful sexual behaviour in children and adolescents.
Create a safety plan for the home rather than relying on promises or constant vigilance.
And perhaps most importantly for the tone of The Resource Project:
You do not need to decide today who this child will become.
A child can cause serious sexual harm that must be addressed without that behaviour becoming the entirety of their identity. At the same time, compassion for the child who caused harm must never come at the expense of the safety, voice or recovery of the child who experienced it.
There is resources and support for children who have harmed other children through acts of COCSA with the goal of prevention future acts.