Dyadic Types of Sibling Sexual Coercion

Sibling sexual abuse seems to be the most prevalent form of sexual abuse in the family context. This study used the Sexual Coercion Scale of the Revised Conflict Tactics Scales - Sibling Version (Straus et al. 1995) to measure the extent of sibling sexual coercion in a sample of 590 Portuguese university students. Prevalence: 11% of male students and 5% of female students had sexually coerced a sibling in the year when the participant was about 13 years old or in another year. Chronicity: When there was sexual coercion in a sibling relationship, it was perpetrated an average of 22.4 (mean) times by males and 9.1 times by females. Dyadic Concordance Types (DCT's) revealed that in 26% there was only one perpetrator who was Male-Only, in 19% the perpetrator was Female-Only and more than half (55%) Both coerced. From the perspective of female respondents, in 50% of the cases the perpetrator was a Male-Only, in 31% Female-Only and in 19% Both coerced. Conclusions: Sexual coercion of siblings is probably more frequent than generally realized. Males had higher rates of perpetration, but the percentage of females was substantial. These results suggest a need to expand research to understand the etiology of sibling sexual coercion by females as well as males, understand causes, risk factors and to expand efforts to reduce sexual coercion in sibling relationships.