Start here....
"Fifty percent of offenses committed against children younger than 6 years were committed by a family member, as were 42% of acts committed
against children 6 to 11 years old and 24% against children
12 to 17 years old. The study by Abel and Harlow found that 68% of “child molesters” had molested a family member; 30% had molested a stepchild, a foster child, or an adopted child; 19% had molested 1 or more of their biologic children; 18% had molested a niece or nephew; and
5% had molested a grandchild."
(Mayo Clinic, "A Profile of Pedophilia: Definition, Characteristics of Offenders, 2007)