"And then when my mother died, it ended in a strange way, because then it was with these five children to take care of," he said. "Overall, it's not something I like to talk about."
O & # 39; Donnell was 10 years old when his mother, Roseann, died of breast cancer.
His father, Edward, died in 2015 from cancer.
O & # 39; Donnell shares the revelation in his upcoming book "Ladies Who Punch: The Explosive Inside Story by & # 39; The View & # 39;" which will be published in April 2.
"Of course, it all changes," he told Variety of the abuse. "Every child who is put in that position, especially by someone in the family, feels completely powerless and stuck, because the person you would say is the person who does it."
The former talk show presenter was an explicit advocate for other alleged victims of sexual abuse including Dylan Farrow.
He said he had forgiven his father, although he felt that something he had done to her and his brothers was "unforgivable".
"You are 50 years old and you still can't get mad at what your father did in 1970," said O & # 39; Donnell. "You have to work out for yourself and find a place for it in your life and not repeat it forever."