Sibling Sexual Abuse (SSA): Harmful Sexual Behaviors vs. Normal Curiosity

As a therapist who has worked for many years with trauma survivors, and as a parent who has a child impacted by SSA, I know how confusing, painful, and isolating this topic can be. Sexual behavior between siblings falls on a spectrum—from normal curiosity to deeply harmful abuse—and as a parent or professional, it’s vital we understand the difference. Ignoring worrying behavior or dismissing it as “kids will be kids” or “normal curiosity” can leave children unprotected and wounded.

Why this topic matters

Many people assume sexual abuse always involves an adult abusing a child. But in fact, one of the most under-recognized forms of child sexual abuse is between siblings.  When sibling sexual behavior happens, it can have long-term effects: trauma, shame, disrupted relationships, anxiety,and depression.

Normal sexual curiosity in children: what it looks like

Children are naturally curious about their bodies and about sexuality. That is developmentally typical. Some indicators of age-appropriate curiosity include:

• Occasional exploring or “show me yours” type behavior when children are very young (e.g., preschool or early school age).

• The behavior stops when grown-ups intervenes or when the children are educated on body safety, and there is no lasting distress.

• No force, coercion, secretiveness, or significant power imbalance.

• Behaviors are brief —not ongoing, compulsive or escalating.

• The children involved show no signs of trauma or emotional harm afterward.

In those cases, the event becomes a “teachable moment”—we step in to talk about body safety, boundaries, consent (“our swimsuit parts stay covered,” “if someone says stop, we stop”), and then redirect children into healthier play.

As a parent, it’s important to stay calm, stay present, and see the behavior without panic—but also without dismissiveness.

When it crosses the line: harmful sexual behavior / sibling sexual abuse

When does sibling sexual behavior become harmful? The difference often lies in power, consent, secrecy, coercion, age or developmental difference, and the impact on the child who is harmed. The definition offered on siblingsexualtrauma.com is:

“Sibling sexual trauma (SST) is the effect of sexual behavior that:

1) Happens between children who share the same parents and/or the same home

2) Goes beyond age-appropriate mutual curiosity

3) Causes emotional &/or physical harm.”

Key warning signs and features of harmful behavior include:

• A sibling uses force, manipulation, threat, or enticement to get another sibling to engage in sexual acts.

• There is a clear power imbalance (older vs younger, larger vs smaller, more mature vs less mature).

• Sexual behavior is ongoing, repeated, secretive, or escalating—not a one-time curiosit

• The younger sibling shows distress, shame, fear, avoidance, regressions in sleep, behavior, school performance.

• The behavior involves penetration, forced watching of sexual activity or pornography, or sexual contact not appropriate to age and development.

As a therapist-parent, I learned that even if the child causing harm is also a child, you can’t simply treat it as “misbehavior”. It is trauma! Professional involvement, therapeutic support and family safety planning for both children are likely needed.

Practical guidance for parents and caregivers

Here are some steps and tips that helped me, both as a parent and as a therapist working with families:

1. Pause the situation
   — If you become aware of sexual behavior between siblings, calmly but firmly stop the interaction. Supervise and separate if needed.
   — Create a safe space for the sibling who was harmed—not blaming or shaming them, but listening and validating their feelings.

2. Talk openly (age-appropriately) about body safety, boundaries, consent
   — Use simple language: “Your body belongs to you; you have the right to say yes or no.”
   — Reinforce that “if someone made you feel uncomfortable, you can tell me.”
   — For younger children read books or play games on body safety and consent

3. Seek professional support early
   — If the sexual behavior shows signs of coercion, secrecy, distress, or power imbalance, consult a therapist experienced in child sexual abuse and sibling sexual trauma.
   — Don’t wait for a full disclosure—clinical signs (sleep disturbance, avoidance, sudden aggression) can indicate trauma.

4. Protect and supervise
   — Increase supervision of sibling interactions. Consider separate sleeping arrangements or spaces if needed.
   — Monitor online activity and media exposure—not just for the sibling causing harm but for the harmed child too.
   — Make a family safety plan with rules about bedrooms, doors, privacy, and how to report if something happens.

5. Support both children
   — The harmed child needs safety, validation, therapeutic care.
   — The child who caused harm needs therapeutic work to understand boundaries, empathy, power, impulse control, and to prevent future harm.
   — As a parent, you also need support—this is heavy. You might feel guilt, anger, confusion, shame.

6. Avoid blame or dismissal
   — For the harmed child: Never minimize. Saying “oh it was just curiosity” when they were hurt sends the message their pain doesn’t matter.
   — For the child who caused harm: Don’t view them as a “bad kid”, but hold firm accountability. This is a behavior that must stop—not a label that cannot change. Often this behavior stops with education.

7. Create a culture of openness
   — Regularly talk about healthy relationships, bodies, privacy, respect.
   — Encourage siblings to talk about uncomfortable situations without fear.

Resources for parents and professionals

Here are some resources that I regularly refer clients and colleagues to:

• Sibling Sexual Trauma: siblingsexualtrauma.com

• 5Waves: 5waves.org

• Stop it now: stopitnow.org

• My Body Belongs to Me Toolkit: My-Body-Belongs-To-Me-Toolkit.pdf

Final thoughts

As a parent and as a therapist, here are some take-aways I hold close:

• You are not alone. This issue is more common than many believe—but that doesn’t mean it is easy.

• Your response matters—calm, caring, boundary-setting, and timely intervention make a difference for both children.

• Help and support are available—for the harmed child, the child who caused harm, and for you as a parent.

• Healing takes time, but with trust, therapy, and safe family dynamics, children can recover and families can rebuild.

If you’re reading this and thinking, “That might be what’s happening in my home,” please act. The sooner you create safety, trust, boundaries and professional help, the sooner healing can begin.

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