This is a partial transcript from "The O'Reilly Factor," August 22, 2006, that has been edited for clarity.

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BILL O'REILLY, HOST: In the "Impact" segment tonight, I believe most Americans see John Mark Karr as a villain. Personally, he makes my skin crawl. Here is more of what Karr allegedly said to a police informant.

(BEGIN AUDIO CLIP)

JOHN MARK KARR: I kiss little girls on the mouth and they've actually, most of the time, initiated the kiss. But I've never done any of those things that are textbook considered, you know, you better not do that.

(END AUDIO CLIP)

O'REILLY: The question: How did Karr and others like him get that way?

Joining us now from Baltimore, Dr. Fred Berlin, founder of the Sexual Disorders Clinic at Johns Hopkins University.

All right. We have this debate about people that do things that are not in the mainstream. Do you believe pedophilia is inherent, you're born with it?

FRED BERLIN, M.D., SEXUAL DISORDERS CLINIC AT JOHNS HOPKINS UNIVERSITY: Let me define it first. Pedophilia is a condition in which a person's sexual condition is directed either in whole or in part towards young children. So that's what we're talking about. And just as not all drunk drivers are alcoholics, not everyone who abuses a child has pedophilia.

Now in terms of the cause of pedophilia, it's a good question, but like asking what is the cause of heterosexuality or what's the cause of homosexuality — what we know is those things are not determined by a voluntary choice. As a little boy I didn't sit down and say to myself, "Do you want to grow up to be attracted to women, men, boys, or girls?" I discovered that I am attracted to women. And similarly, the man that is attracted sexually to children discovers that he is afflicted with aberration of sexual makeup. He isn't that way because he was a bad little child who decided to grow up to be different.

O'REILLY: All right. Here is my problem with that. That the basic human instinct to reproduce produces heterosexuals, so it's obvious that most people are born that way, there wouldn't be a human race.

No. 2, other doctors, in fact, we had one on last week, Andrea Macari believes this is solely acquired. Let's roll the tape there.

(BEGIN VIDEO CLIP)

ANDREA MACARI, PHD, CLINICAL PSYCHOLOGIST: It goes back to a concept called classical conditioning. Men are not naturally sexually aroused by children. It's a learned behavior. Just like Pavlov's dogs learn to salivate at the presentation of a bell. These men, when they look at images of children become sexually aroused.

O'REILLY: You don't believe anyone is born a pedophile?

MACARI: No. Absolutely not.

O'REILLY: So they acquire it by looking at this kind of stuff?

MACARI: Absolutely.

O'REILLY: All right.

(END VIDEO CLIP)

O'REILLY: OK. Doctor, so what say you? I mean, it's confusing.

BERLIN: Again, that's...

O'REILLY: Go ahead.

BERLIN: Sorry to interrupt. That's the theory. The question is what's the evidence to support the theory? Sometimes we just have to use a little bit of common sense. At what point did I make the decision as a little child to grow up to be heterosexual? Just our own life experience tells us that something is there that wells up inside of us that isn't there because we chose to have it that way.

O'REILLY: No, but you can choose how to act out on any kind of sexuality. Just as you can choose what your diet is and you can choose what beverage to drink. These are all natural impulses. You have to eat to live. You have to drink to live and you reproduce. This is inherent in you when you are born.

BERLIN: Absolutely.

O'REILLY: This is a key question for society. I believe this Karr guy is evil. I believe he's evil. But if he's born with it and can't control himself, then I'm wrong.

BERLIN: Let me get away from Karr for a moment and just make the point that, yes, it's not a person's fault that he has pedophilia, but it's his responsibility to do something about it, just as is the case with drug addiction and alcoholism, doing something about it may mean getting access to proper treatment.

God or nature put the sex drive into us for a very important reason and that's literally the preservation of the human race. So when that powerful drive that we currently wants to be satisfied gets aimed, for whatever reason, in the wrong direction, for example toward children, it still recurrently wants to be satisfied. So absolutely there is a responsibility, but you may need help.

O'REILLY: OK. So what you're saying, a guy like Karr has the power to control himself.

BERLIN: I am saying that like the severe alcoholic or the severe drug addict, now I don't want to make it specific to him, but there are individuals who want to do the right thing, but need help in order to be able to accomplish that goal.

And part of the problem in our society is we're not allowing for that possibility. I'm a physician. I have people, parents, who bring to me their 16-year-old son. The son is confiding that he's not attracted to people his own age, he's recurrently wanting to have sex with five year olds. It accomplishes nothing to just say he's evil. I need to understand what it is he's coping with and I need to try to find a way to help this young man and this family so he's going to be able to lead his life responsibly.

O'REILLY: All right. But I believe every human being has the power to regulate their behavior. I do. Doctor, pleasure to have you.

BERLIN: Sometimes with help.

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