She is married with at least one child and has an income of about $20,000. She is in her 30s rarely goes to the movies, watches more than eight hours of television a week, carries at least one major credit card and is politically conservative. There are thousands like her in the Maryland suburbs.

She is a Frederick's of Hollywood woman.

"They giggle first, then they buy," said Frederick Mellinger, the purveyor of "passion fashions," the seller of soft-core seductiveness to suburban housewives who is opening his fourth retail outlet in Maryland next week.

The company, which earned$25 million last year selling peek-a-boo undies, see-through peignoir sets and push-up bras, decided to take a survey of the average customer. What the survey revealed would surprise those who thought Frederick's of Hollywood was an X-rated mail order catalogue in a plain brown wrapper.

"We appeal to middle America," said Tricia McBride supervisor of the Frederick's store is the Landover Mall.

Indeed, of the 120 Frederick's of Hollywood outlets across the country, allbut three are located in suburban shopping centers. The appeal is so strong in the suburbs of Washington that the firmis opening its second Prince George's store, this one located in Forestville, just south down the road from Andrews AirForce Base.

"The bedroom area around Washington is a good market for us," said Mellinger. "We feel the area can take more than we have now."

The second Prince George's storewas proposed, explained Mellinger, after the company realized that a hefty chunk of the 10 million mail order customer lived in the area.

"Maybe it's because there are more women than men in the Washington area," he said. "Certainly, we have a lot of customers in Maryland."

Frederick's openedits first Maryland outlet eight years in Columbia. In 1973, it branched out to the Landover Mall, then to Rosedale (onthe outskirts of Baltimore) and now to Forestville. It is currently looking for the right spot in Northern Virginia.

"We have a lot of angry Virginias who have to drive over here," said McBride.

Take Mary Dallas, for example. She drove from Falls Church to Landover the other day to plunk down $50 in cash for a slinky red disco dress and a black "push-up" bra. Wearing a fluffy brown wig, spidery eyelashes and a denim jacket with rhinestones spelling D-A-L-L-A-S, the 37-year-old said she shops at Frederick's because, "They gotsexy clothes."

The average Frederick's customer spends $45 at a time, the survey showed, and most likely will purchase a laced, padded push-up bra ($15) or a padded "Fanny Former" girdle ($9.50) or nylon "Baby Doll" lingerie ($15). The "gag items," like Playboy Bunny costumes or heart-shaped G-strings, glittery pasties or "Frederick's Kissable Bust and Body Balm," are big sellers for holidays, like Valentine's Day, Christmas and Mother's Day.

"It's clean sexy," said saleswoman Barbara Wall. "It's not blatant. It's titilating,but not pornographic."

At the Columbia Mall store, manager Diane Spano said housewives from Pennsylvania and West Virginia drive to the shop twice a year to stock up on items.

"It's more openly accepted now," she said. "People aren'tembarrassed to buy something sexy like they were years ago. The image has changed. I think the demand is here for it."

She remembers the day a group of senior citizens wandered into the store. "One little white-haired old lady -- she must have been in her 70s -- said she had heard that if you don't have anything in the back, Frederick's will put it there," Spano said.

"With her friends giggling, the woman tried on a padded girdle. "she loved it," Spano said. "She came out of the dressing room and said how one of the men at the senior citizen home would fall in love with her because she had a tush on her. The rest of the customers applauded."

"Frederick's customers also include husbands, many of whom say the department store lingerie counters are too tame.

"I suppose it's that "Total Woman' thing or something,' said McBride.

"They want their wives to be seductive."

Saleswoman Helen Miller recalled a middle-aged woman who frantically rushed into Frederick's one day, saying her marriagewas on the rocks. "She bought all kinds of things," Millersaid, Pasties, a G-string, you name it, she bought it."

It may have worked, Miller said. The woman never came back.

"Oh God, we've received thousands of letters telling us how we've saved marriages," Frederick Mellinger said. "We feel we're performing a necessity, keeping the homes together."

The next survey the company is considering is one that would monitor the divorce rate in an area before and after a Frederick's outlet opened.

Frederick's of Hollywood beganin 1946 as Freddy's Fifth Avenue in New York, selling blacklace underwear. Mellinger then moved to Los Angeles and went into the mail order business. By the early 1950s he had opened a few stores in the Hollywood area, selling mostly toentertainers and budding starlets. He became famous for lines like, "You'll never sue me for nonsupport" and for pioneering such fashion staples as the padded bra, sheer panty hose, padded girdles and hot pants.

"This country is very well endowed," says Mellinger. "Women's lib is fine in theory, but as a friend used to say, "Vive la difference," long live the difference."

As for his critics, who claim Frederick's of Hollywood is demeaning to women, that the "passion fashions" he sells are fantasies, that he exploits women's insecurities and encourages them to use their bodies, not their brains, the 64-year-old Mellinger just sighs.

Federick's of Hollywood does not sell sex, he says. "I think we're selling a dream come true."