Teenage abuser says he "got told too young" that father raped his sisters

A teenager said that finding out that his own father had raped his sisters may have caused him to begin sexually abusing his younger niece, a court has heard.
The teenager, now aged 19, admitted the abuse to gardaí and told them he stopped the abuse when he was 14, two years after it began. The victim was aged between seven and nine. The teen admitted molesting her numerous times.