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What Do We Know?

Simply Put, Not Enough

Sibling sexual trauma is common, but hidden.

  • The best estimate based on current research is that only about 12% of those who are affected by sibling sexual trauma ever tell anyone about it [1]. But, it is impossible to truly measure how many never tell, even anonymously to a researcher.

  • With that in mind, 5WAVES estimates that 2-5% of children are affected by sibling sexual trauma [2]. This means that it is approximately as common as childhood food allergies [3].

  • Leading researchers suspect that sibling sexual trauma is one of the most prevalent forms of child sexual abuse [4].

[1] Finkelhor 1980, Townsend 2016 

[2] Finkelhor 1980, Strong 2022, Relva 2017, Cawson et al 2000Stroebel et al 2013,

Griffee et al 2014, Mathews et al 2024)

[3] NCHS Data Brief, 2008

[4] Yates & Allardyce, 2021, SARSAS/Strong, 2022, Stathopoulos, 2012, Bertele & Talmon 2021

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Sibling sexual trauma is real.  It is different than "playing doctor," but hard to distinguish. The consequences are serious and lasting.

  • Sibling sexual harm starts earlier, lasts longer, and is more frequent and severe than other child sexual abuse. In half of all cases, the traumatizing behavior toward a child begins before their 8th birthday, and lasts more than 5 years [5]

  • The consequences of sibling incest are as serious for the survivor as adult-child incest.  They include anxiety, depression, shame, Complex PTSD, difficulty maintaining stable and trusting relationships, stress-related pain and physical illness, increased risk for substance addiction, eating disorders, self-harm, suicide, sexual exploitation and victimization into adulthood [6]

  • Children who bear the responsibility for sexually harming a sibling, or who felt at the time that they were a willing participant, are still likely to suffer lifelong negative consequences including shame, depression, anxiety, low self-esteem, and increased risk for suicide and addiction [7].

  • Adults, including parents and professionals, find it difficult to accurately assess and appropriately respond when they learn of sexual behavior in children. In a survey of professionals who respond to reports of child sexual abuse in the UK, 73% reported they had received  inadequate training about sibling sexual behavior, with many reporting no education or training whatsoever [8].

[5] Kreinert and Walsh 2011, Finkelhor 1980,  Bertele and Talmon 2021, deJong 1989

[6] Carlson, 2011, Cyr et al 2002, Falcao 2014, Katz et al 2020, Laviola 1992, Rudd & Herzberger 1999Shaw et al 2000

[7] Marmor & Tener 2022, Tener et al 2017, Kjellgren2017, Allardyce & McAfee 201

[8] Noble, 2022, Sibling Sexual Abuse Professional Survey Report

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Children and teens who cause sexual harm to their siblings need to take responsibility, and need extra guidance, supervision and professional help.  However, there are many who do not continue to sexually harm children into adulthood.
  • More than ⅓ of sexual harm to children and teens is caused by other children or teens [9].  

  • Sexually abusive behavior toward young children appears to peak at age 13-14 [10].

  • Although the harm to their siblings is serious and real, and the short-term risk for relapse is high, factors that lead children and teens to make this tragic choice are very different than for adults who sexually abuse children [11].

  • Several studies based on cases entered into the criminal legal system have found that less than 10% of adolescents who are charged with a sexual offense of any kind will be arrested for another sexual offense as an adult [12]. Although most instances of sexual harm are never recognized by the legal system, and there are no studies specific to sibling sexual abuse,  these studies suggest that a large percentage of juveniles who engage in harmful sexual behavior do not continue to do so as an adult. 

Cautions on the use of these studies:

  • General estimates of reoffense rates cannot predict whether any individual person will cause harm again. Every situation is unique, and adults must make victims' and children's safety and healing top priority.

  • Research is needed that looks at risks specifically for those who have sexually harmed a sibling, and that include data from other sources in addition to the criminal legal system.

[9] Finkelhor, et al 2009, Hackett 2013, Grant et al 2009, Snyder 2000, Gerwitz-Meydan & Finkelhor, 2019, Mathews et al 2024

[10]  Boyd & Bromfield 2005, Finkelhor Ormrod & Chafin 2009Snyder 2000

[11]  Przybylski 2015, Grant et al 2009, Hackett et al 2013, Lussier & Blokland 2013, McKibbin 2017, McKillop et al 2015, Worling 2013

[12]   Caldwell 2010, NSPCC 2021, McKillop 2015, Boyd & Bromfield 2006, Letourneau 2008, Przybulski 2015

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