 Similarly, Cyr and colleagues found that about 70% of sibling incest involved sexual penetration, substantially higher than other forms of incest.Bass and colleagues write that "sibling incest occurs at a frequency that rivals and may even exceed other forms of incest," yet only 11% of studies into child sex abuse examined sibling perpetrators.Rayment and Owen report that "[in comparison of] the offending patterns of sibling offenders with other teenage sex offenders [...] Sibling abusers admitted to more sexual offences, had a longer offending history and a majority engaged in more intrusive sexual behaviour than other adolescent sex offenders.