Sibling sexual abuse

ACSSA Research Summary No. 3 – October 2012

Prevalence and incidence

Very little is known about the prevalence of sibling sexual abuse (Caffaro & Conn-Caffaro, 2005; Carlson et al., 2006). Cases that come to the attention of the authorities may also not be typical of the types of abuses occurring but it is difficult to know for sure. This is because the cases that are known may be the extreme or more violent cases that families cannot ignore or deny and therefore are reported and/or documented. Additionally, national surveys such as the Personal Safety Survey (by the Australian Bureau of Statistics) do not include siblings as a category for intra-familial sexual abuse - or siblings are incorporated under the heading "family member" and therefore not separately identifiable.

The studies that do present prevalence data put sibling sexual abuse as more common than other forms of intra-familial sexual abuse (Monahan, 2010; Pratt et al., 2010; Rowntree, 2007; Thompson, 2009). Caffaro and Conn-Caffaro (2005) estimated that sibling sexual abuse occurred "three to five times as often as the most frequently cited form" (p. 609), father to daughter child abuse.

In a study of 51 children who had been sexually abused, about half reported being abused by a sibling (Shaw, Lewis, Loeb, Rosado, & Rodriguez, 2000). A study by the National Society for the Prevention of Cruelty to Children (UK) interviewed 2,869 young people between 18-24. The researchers found that of those who had been abused as children, 43% were victims of sibling sexual abuse (McVeigh, 2003). Further research is important to ascertain a clearer picture of prevalence in order to create awareness.

One US empirical analysis of offender, victim and event characteristics from national police records (Krienert & Walsh, 2011) revealed that of 13,013 incidents of sibling sexual abuse reported to police between 2000 and 2007, that:

  • 82% of victims were under 13;
  • 71% of the incidents involved female victims;
  • 13% of the sample involved multiple victims;
  • males accounted for 92% of sibling sexual abuse offenders;
  • 95% of offenders were older than their victims;
  • the average age gap was 5.5 years;
  • the most common dyadic relationship was male abusive sibling and female victim; and
  • one-quarter of the sample was male-male sibling sexual abuse.