Colin admits that he has molested his sister on two different occasions and that he has also molested several other young girls. In the video above from Friday's episode of Dr. Phil, the now 18-year-old, who molested his younger sibling when she was 11 and 13, explains the thought process that led to the molestations.

“I just wasn’t really thinking about anything other than sex. I just wanted my needs met,” Colin says. “I realize that it was wrong now, but at the time, it didn’t really feel wrong; it felt right for me. But I realize now that that was messed up what I did.”

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Dr. Phil asks him, “How do you feel about what you’ve done to your sister?”

“I feel terrible about it. I never planned on hurting my sister. I love my sister. I apologize,” he says.

WATCH: Teen Describes Being Molested By Her Brother On Two Occasions

After Colin inappropriately touched his sister, their mom never called the authorities. She sent him to a counselor but says she didn't like the advice, so she removed him from the counselor's care. Child Protective Services became involved in the case after his second offense against his sister, and Colin was eventually removed the family home. He spent time in four different group homes and has been enrolled in multiple programs for sex offenders but has never completed any of them, stating that he is just “lazy.”

On Friday's episode, hear why his sister, Addison, now 17, says she partially blames her parents for her brother’s behavior. And, is Colin ready to finally get help for his behavior? Check here to see where you can watch.

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Dr. Phil To Parents Of 18-Year-Old Sexual Predator: 'He’s About As High A Risk For Re-Offense As I’ve Ever Met'