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Study finds risk and protective factors for sibling sexual abuse

A new Australian Catholic University (ACU) study has found sibling sexual abuse (SSA) is most often demonstrated by male siblings with a history of maltreatment or a learning disability.

The research, funded by Bravehearts Foundation, systematically reviewed 39 international studies to identify key risk and protective factors of SSA, which is one of the most common forms of intra-familial child sexual abuse.

Lead researcher Douglas Russell, a Senior Research Officer at ACU's Institute of Child Protection Studies (ICPS), said despite its prevalence, SSA was understudied, leaving children at risk of harm.

"As is the case with all types of child abuse, incidents and harm are magnified in the dark. We need to put a spotlight on sibling sexual abuse and not shy away from it because it is uncomfortable to talk about," he said.

"Previous research has suggested sibling sexual abuse is up to three times more likely to occur than sexual abuse by a parent. Parents and caregivers have a responsibility to safeguard their children from harm, and that includes harm caused at the hands of a sibling."

Among the findings, the research, published in Child Abuse & Neglect and co-authored with ICPS Director Professor Daryl Higgins and ICPS research officers Dr Sebastian Trew, Gabrielle Hunt, and Jessica Dickson, showed:

• Perpetrators of SSA were most likely to be male adolescent siblings with histories of parent-child abuse, learning disabilities, drug use, and exposure to family conflict, violence, disadvantage, and pornography.
• Being female and pre-adolescent were individual-level factors that increased the risk of being victimised by a sibling.
• Familial risk factors included a dysfunctional family environment, divorce, parental absence, and blended families (where sibling sexual abuse involved step siblings).
• Contextual risk factors included fundamentalist religious settings, and a patriarchal family structure.
• Protective factors included higher levels of maternal affection, and, in the case of preventing the continuation of abuse, separating siblings, and disclosure or discovery of the abuse by someone else.
• Rates of disclosure to parents were low, ranging from 8 to 69 per cent, with many child victims (mainly females) not revealing sibling sexual abuse until adulthood.
• Parents often responded poorly to disclosures by minimising and disbelieving victimised children.
• Victims of SSA were more likely to make a disclosure to their mother than their father.

Professor Higgins said early detection and prevention of sibling sexual abuse, as well as education and awareness raising for parents and whole-of-family interventions, were paramount for improving outcomes.

He said the review confirmed findings from the landmark Australian Child Maltreatment Study, of which Professor Higgins was a chief investigator, which showed girls were at greater risk of SSA, mainly from brothers.

"Data published in 2024 from the Australian Child Maltreatment Study found that 1.6 per cent of Australians experienced sibling sexual abuse - 2.3 per cent of women and 0.8 per cent of men," he said.

"We need professionals working in child-facing sectors such as social work, education, psychology, and health to be aware of the risk and protective factors, disclosure patterns, and appropriate responses to sibling sexual abuse to enable effective support for those impacted."

Mr Russell said the new systematic review of research had revealed a comprehensive picture of the risk and protective factors and behaviours involved in sibling sexual abuse, but that greater understandings, and awareness and education for parents and caregivers was needed.

"We need more rigorous research and better support for parents and caregivers to address sibling sexual abuse in families, reduce the stigma and barriers to disclosure for victims, and facilitate access to treatment and intervention for those displaying these harmful sexual behaviours," he said.

View the study