DR. KEVIN MCGOVERN IMAGE: TOM OLIVER

WW: Most experts say sex fetishes are generally OK. How do you know when a line is crossed?

Kevin McGovern: It's not OK when it becomes an obsession and interferes with your life. Most people who develop fetishes have lower self-esteem, or they've developed a unique pattern of sexual arousal that doesn't include people.

Why do some people who have trouble interacting with other people veer into things that we tend to think of as perverse?

It's safer. If you're into objects, you don't have to have a personal connection with someone. There's no performance anxiety. If you're in love with a pair of underpants, you don't have to worry about rejection.

How do they find their fetishes?

Some people find a fetish by accident. Like, you go into the laundry and find underwear belonging to a sister or mother or aunt. One classic person I can think of started to break into homes and look through clothing. Then he would go through their lingerie and leave his symbol behind.

What do you mean?

Well, he would masturbate and leave semen and put the underwear back into the dresser drawer.

Is burglary always part of the fetish?

No, sometimes you'll find these guys at Victoria's Secret, looking at panties to get aroused.

New underwear? But isn't part of the appeal that they belong to someone else?

Not always. Some people like fresh, virgin underwear; some people like used. It varies. There are people who literally prefer soiled underwear versus washed underwear versus some who--and this is mostly a male thing--only want fresh, new, untouched underwear.

Why is this mainly a male thing?

I think men are more eroticized by visual cues. Women are more about relationships. Fetishism is arousal from an object, not a relationship with someone else.

Where's the line between the guy who steals thousands of panties and the guy who likes his wife to leave her underwear on during sex?

But there's the important thing. He wants his wife to wear erotic things as a form of their sexuality.

So it's more enhancing their relationship rather than excluding it.

Sure. Good. Massage lotions, gimmicks, clothing, erotic materials, nice tuxedos, nice dresses. The problem is when the other person says, "Honey, I would rather sleep with your underpants than you."

Is there any risk factor involved?

Some people destroy their families. If your lover walks in and finds you cross-dressing and masturbating, it's not a pretty scene. I've had someone who goes into a health club and steals women's underwear. He may have to hide in the showers. He may masturbate while doing that and eventually get caught. I've had people who have been inadvertently found in a house and beaten up. I've had people with guns pulled on them. You talk about erectile failure....

What about Sung Koo Kim, who allegedly stole 3,000 pairs of underwear?

He's a collector, a connoisseur. If these allegations are accurate, he somehow got hooked. It became a fascination. There's a certain risk factor in getting caught that is usually some kind of a rush. Why couldn't that person just go to Penney's and give money to the clerk and say, "This is for my wife"? He wants it exciting. The thought that it had been christened by someone was highly arousing. Bodily odors can be a big deal.

Does the fetish feed into a criminal impulse in any way?

No, because most people are law-abiding. They buy their things and use them at home, and they don't get into the big stuff of breaking and entering or hiding in bathrom stalls or putting up cameras. Only a small percentage of people who have a fetish get into the criminal world.

So what do you say to someone who searches for underwear in a stranger's house?

I take a very direct behavioral approach. I have them give me a history of how this all began. I have them look at the natural consequences of what can happen and have them begin engaging in more fruitful relationships.

They're still high-functioning, right?

Well, sure. You wouldn't know. If I were to underscore one thing, almost all people who have a fetish are not going to act out. They're not going to hurt people. They do it because they like their hobby, and if they act out, the hobby is over. They'll be caught.