Imagine what it must be like to have had Jayne Mansfield, the sex symbol of the '50s and '60s, as Mom. Although she died when her daughter Mariska Hargitay was 3 years old, the late actress casts a long shadow.

Her mother's voluptuous public image troubled her, at least early on, Hargitay acknowledged. Indeed, it determined the roles she went for.

"I played lots of tomboys, wearing flannel shirts, jean and boots," she said. "On some unconscious level, I was shying away from those sexual roles because of my mother. But as I got older, I changed my mind. I now look forward to doing all kinds of parts, including those that are sexual and sensual."

At the moment her character is the straight-and-narrow, no-frills Olivia Benson on "Law & Order: Special Victims Unit," which moves this week to Fridays at 10 p.m. on NBC.

"Olivia is an extremely independent and professional woman who is seeking some kind of sense of fairness in the world," said the tall, striking Hargitay, who bears little resemblance to her mother. She spoke in her lamp- and candle-lit -- yes, candle-lit -- trailer near Manhattan's Little Italy, where an episode was being shot.

"Olivia is completely empathetic and feels things deeply," she said "I think she may be an unprecedented woman detective on TV. She's allowed to be female and gentle in a man's world."

"SVU," a spinoff from the long-running "Law & Order," centers on Benson and her partner, Elliot Stabler, played by Christopher Meloni, as they solve particularly unpleasant sex crimes. Like "Law & Order," it is a story-driven drama, although the characters' personal lives play more of a role in this one than they do on "L&O."

Although there's undeniable chemistry between the two leads, and Hargitay is often asked whether romantic sparks will fly between the two characters, she answers with a firm "No! They are professionals, and Elliot is a happily married man."

Best known for her stint as the fragile, fragmented Cynthia Hooper, the girlfriend of Dr. Greene on "ER" during the 1997-98 season, Hargitay is a far cry from any Jayne Mansfield image the public may still have.

Articulate and impassioned, Hargitay, 36 this month, expresses deeply held convictions. "There are no accidents in life," she said. "Things happen for a reason. Our job is just to slow down and listen to the universe. And, if we do, we'll find the reasons. Listen, and the answers will follow."

Mariska (pronounced Mar-ISH-ka) Hargitay, a native of Los Angeles, describes herself as "spiritual. I was raised as a Roman Catholic and went to an all-girls Catholic high school. I definitely call myself a Christian. I love God a lot and go to church whenever I can. And that's all I'll say about that."

In her interpersonal style, Hargitay is hearty, enthusiastic and, well, affably aggressive. She prefers the term "extroverted."

Consider the way she spoke to producer Dick Wolf at her callback audition. "When I saw other actresses in the room, I walked into Dick Wolf's office and said, `You gotta be kidding! What's with the other women? This is my part, sweetheart. Tell them to go home.' "

He didn't send anyone home, but that didn't intimidate Hargitay. After she auditioned, she felt free to ask him for acting directions.

"I said to him, `Tweak me.' He said, `You want to be tweaked?' I said, `I didn't drive all this way not to be tweaked.' So he gave me a note, which was, of course, genius. I did what he suggested and told him, `That was good.' He laughed and I left. Two-and-a-half weeks later, he called and said, `You're flying to New York to test for the role.' "

Wolf's tips apparently helped Hargitay bring a number of traits to the Benson character. "I'm more impulsive and instinctual than she is," she said. "She's more calculating, although sometimes she lets it out. Other times, she has to squelch what she's feeling.

"My challenge as an actress is in maintaining the balance and finding the boundaries between her and me. One profound difference is that Olivia doesn't want to get married or have kids. I can't imagine that. My goals in life have always been to act and have a family. I have three godchildren whom I adore."

Hargitay's love of children goes way back. In high school, she worked with abused children living in a shelter. "If I weren't an actress, I'd probably be a teacher or psychologist." (At one point during the interview, she dashed out the trailer door because she thought she heard a child crying.)

Hargitay stressed that she never lived the Hollywood life, despite her parentage. Her father, Miklos "Mickey" Hargitay, was also a colorful public figure. Formerly a weightlifter, he simultaneously held the titles Mr. World, Mr. America and Mr. Universe. He was not averse to engaging in wild promotional stunts with his wife, such as twirling the bikini-clad Mansfield over his head. Mickey Hargitay, whom his daughter calls Pop, was Mansfield's second husband. He now makes his living in real estate.

Mansfield was 34 when she died in a June 1967, car-truck crash near New Orleans that also killed two men and two of her pet chihuahuas. Her children Mariska (then called Marie), 3; Zoltan, 6; and Miklos (Mickey Jr.), 8, were injured.

Hargitay grew up protected from the glitz and hoopla that surrounded her parents' lives and her mother's legendary Hollywood image. Two years after Mansfield's death, Mickey Hargitay married a flight attendant. "My parents' friends were not in [show] business, and we spent a lot of time, especially in the summers, traveling. We went to Hungary [home of her paternal grandparents] and Italy when my Dad was still appearing in spaghetti Westerns."

She learned to speak French and Hungarian as well as Italian, and Italy is still one of her favorite places. "As soon as I'm on a hiatus, I'm off to Italy," she said.

Hargitay got into acting almost serendipitously. She always had a flair for comedy -- "Being able to make people laugh is like a drug," she said -- but in high school, she decided on a whim to audition for a play that was not comedic. She landed the lead in the emotionally charged "Women's Work," which deals with abortion. And she found herself "very comfortable onstage and realized that's what I wanted to do -- act. I came to that decision all on my own. None of my five brothers or sisters were interested in the field."

Hargitay majored in theater at UCLA and shortly after she graduated, appeared on the brief series "Downtown." Other television credits include stints as a cast member on CBS's "Tequila & Bonetti" (1992); "Can't Hurry Love" (1995-96); and "Falcon Crest" (1987-89); and guest appearances on "Seinfeld," "Ellen" and "thirtysomething." Among her film credits: small roles in David E. Kelley's "Lake Placid," David Lynch's "Hotel Room" and the critically respected "Leaving Las Vegas."

Her professional turning point was appearing on "ER." The experience, she said, was also an artistic watershed. "You learn so much by working with and watching good people."

She lists Meryl Streep and Kevin Spacey among the actors she admires and calls the two performers her "aesthetic mentors," even though she's never worked with them.

Hargitay defined good acting as "the ability to be a window for audiences to look into their own lives. Good acting is cutting it open and letting it out. It's so hard," she said. "We walk about with all these layers, protections, and defenses. It's difficult to peel it all away. That's why actors may seem so overly sensitive. To do what they do -- when it's working --

they have to be open wounds."

At the moment, Hargitay's thoughts are focused on the challenge of appearing on a series that deals with rugged subject matter. Some of the "SVU" stories, specifically those dealing with children, are very difficult for her, she said. "In an episode about an 8-year-old who is sexually assaulted and killed, you really see how fragile kids are and how susceptible they are to pedophiles. It makes me want to kill people who molest children.

"Yet, the beauty of the scripts is that there's nothing black and white in them. They're all gray. Of course, killing a child or poisoning his life is evil, but when you get to meet some of these pedophiles or child abusers, you realize that they too were victims of child abuse. They really don't know how to relate to a child in any other way."

To achieve a level of truthfulness in her performance, Hargitay spends much of her free time with female detectives of the Special Victims Units in Manhattan and Brooklyn. "The big surprise for me is how human they are. I used to think they had to be totally focused on the job. Get the facts. Get the perp. But these women are not detached. They're emotionally available."

One aspect of Olivia's makeup that Hargitay is in tune with is that "sense of loss and trying to fill in the gaps," she said. "Olivia was raised by a single parent [played in one episode by Elizabeth Ashley] and never knew her father personally. Her knowledge of fathers comes from what she saw at the homes of friends."

Similarly, Hargitay said, her knowledge of her mother is largely based on what others said about her and her public image.

"People would always ask me if I had seen her movies. I was not interested in her film persona. I wanted her to be my mom and know something about who she was: who she loved, what made her sad, and I wanted to know how I was like her. I wanted to hear real stories."

In recent years, Hargitay has reconsidered her mother. She now sees Mansfield as a role model. "I think she was ahead of her time. She was a wonder-woman. She had a career and five children. She was sexy, played the violin and had an amazingly high IQ. She had a zest for life, lived every minute to the fullest. She did it all."

Hargitay hopes to do it all. Besides having her own family, appearing onstage is her ultimate goal, she said. "I want to grow into playing Maggie ["Cat on a Hot Tin Roof"] and Blanche Dubois ["A Streetcar Named Desire"]. For most of my life I've been coming to New York three times a year just to see theater. I'll go to two shows a day. I'm a drug addict for theater. I love it! And whenever I see great acting onstage, I just can't speak, especially to the actors themselves. With movie stars, I'm fine. With theater stars, I can't speak."

Last spring, she was struck dumb -- yet again -- following performances of "Wit," starring Kathleen Calfant (with whom she co-starred in the TV series "Prince Street"); "The Lion in Winter," starring Lawrence Fishburne and Stockard Channing ("She just blows my mind") and especially "Death of a Salesman," starring Brian Dennehy.

But it was Elizabeth Franz's Tony Award-winning performance in that play that rendered her mute.

"Who even thinks about the wife's experience in that play?" Hargitay asked rhetorically. "After the show, I sent Franz a bouquet of flowers. I was afraid she'd think I was a stalker. I didn't think she'd know who I was."

As it turned out, Franz was familiar with Hargitay's work and invited the young actress to talk with her for an hour.

"I felt blessed," said Hargitay. "And that's when I decided I was going to move to New York and work toward playing all these wonderful roles. In Hollywood, you turn 35 and it's over. In New York, it's a different world."

And it was just at that point that Dick Wolf offered her the part of Olivia and she relocated to New York for her new job.

"That's what I mean when I say there are no accidents," she said. "It was meant to be."