The tourist formerly known as Larry Goodwin is most people's idea of a man's man -- in every respect but one.

Chatting this week during a visit to the Vietnam Veterans Memorial, and then over lunch at a Washington restaurant, the broad-shouldered 51-year-old described himself as an ex-Air Force enlisted man (crew chief on C-130 transport planes flying from Guam to Thailand in 1965-67) and a onetime rodeo cowboy back home in Wyoming (his specialty: bareback bronco-riding).

He builds aerobatic biplanes in his spare time at home in Douglas, Wyo. (population 5,000), volunteers in worthy causes and Democratic Party politics, and has worked for the past 23 years as a highly paid technician at a coal-fired power plant in nearby Glenrock. He's also the proud father of two grown children (a 25-year-old son, Travis, and a 23-year-old daughter, Kristi: He keeps snapshots in his wallet) and has been married to the same woman for almost 29 years.

"We've been together a long time, because I love him," said his wife, 49-year-old Vickie Goodwin, who accompanied him here. She was a waitress at the Pink Kitchen in Casper when Larry, then a college student on the GI Bill, first asked her out on a date. "He is," she added, "a really good person." A really good person who shaves his legs, favors pink Magic Kiss lipstick and, on this particular August day on the Mall, was wearing an accordion-pleated gray and white tennis skirt, a frilly puffed-sleeve pink blouse and -- he lifted his thigh-high skirt to reveal -- lacy yellow panties. At 5 feet 10 and 170 pounds, accessorized with a green leather handbag, ladies' watch, sparkly ring and slip-on tennis shoes, he introduced himself as Sissy, the name he's been using for the past two decades.

"It's not so much a fashion statement or a political statement as a fully realized expression of the fact that this is the way I am," Sissy Goodwin explained in a quiet, aw-shucks voice that might have belonged to Gary Cooper. "I'm heterosexual. I've been married for 29 years," he continued. "But I've been this way since age 4 or 5 probably."

With his short, graying hair and moderate beard, Goodwin was clearly making no attempt to fool anyone. He was, unmistakably, a guy in a skirt. When first spotted Tuesday afternoon by a photographer for The Washington Post, he was browsing through T-shirts and souvenirs on sale near the memorial. But he gladly stopped to discuss his appearance with a reporter.

Vickie Goodwin, who is co-director of Wyoming's Powder River Basin Resource Council, a nonprofit environmental group, was off making a fund-raising presentation to potential donors, he said. Sissy, for his part, had just finished participating in the annual convention of Veterans for Peace, an anti-war group that had been meeting at the Arlington Hyatt. It's just one of the causes that Goodwin -- who was treasurer of the Wyoming American Civil Liberties Union and a Carter delegate at the 1980 Democratic National Convention -- has embraced over a lifetime of political activism.

"I'm very well known in Wyoming," he said with just a hint of braggadocio. And, especially in Democratic circles, he is.

"Larry's a guy I've known for a number of years, and he's always been interesting and engaging, but I've never talked to him about his . . . uh . . . give me a word," said former Wyoming governor Mike Sullivan, who served from 1987 to 1995. "I can tell you his wife, Vickie, is really bright and public-spirited," the Democrat said from his law office in Casper. "I've never seen anyone hassle him or reflect a lack of tolerance. I don't think people in Wyoming respond to him any different than they would anywhere else. At the same time, I know people are puzzled."

"Sissy is a very warm, a very sweet person," says Wyoming civil liberties lawyer Laurie Seidenberg, past president of the state ACLU. "He's a delightful person to be around, and a genuinely peaceful person."

Said another ACLU friend, state Executive Director Marvin Johnson: "Frankly, Sissy's got a lot of guts to be dressing like that in a state like Wyoming."

"I'm actually fairly open with my mode of dress," Goodwin himself said, ignoring the drop-jaw, bug-eye, whiplash reactions of passersby on the Mall. "I really love the feel of women's clothes. That's really all I ever wear anymore.

"But I also think it's a survival mechanism. My sister and I grew up in an extremely hostile environment, with both our parents alcoholics and my father very abusive." His sister, he said "has been in and out of mental institutions. I haven't. I believe that my transvestism is my way of dealing with stress."

Transvestism remains mysterious in origin despite decades of scientific research into the behavior and its causes. Along with Robert G. Peterson, a Wyoming psychologist he saw for therapy, Goodwin authored a research paper on the subject, published seven years ago in the Journal of Applied Rehabilitation Counseling. Titled "Psychological Impact of Abuse as It Relates to Transvestism," Goodwin and Peterson's report argued that "transvestism is maladaptive addictive behavior" often brought about by childhood abuse.

"Transvestite behavior later in life, although pleasurable for the subject, is a continuation of abuse," the paper argued. "This is due to the negative social pressures and humiliations by peers and others. This humiliation and rejection creates stress that the individual feels can only be eliminated by cross-dressing."

Maybe; maybe not, said clinical psychologist Richard F. Docter, whose book "Transvestites and Transsexuals: Toward a Theory of Cross-Gender Behavior" is well regarded in the transvestite community.

"We all strive to make sense of our lives and our experiences and our feelings, but the causes of this are a totally open question," said Docter, a professor at California State University at Northridge who has been studying the phenomenon since 1979. "The two explanations that are favored are, first, a biological theory -- that is, something influenced the central nervous system, possibly in utero," he said. "The second theory is that you can learn this behavior through your own social experience, which somehow makes you need to express a different gender." Goodwin's theory, Docter added, is in the second category, "basically kind of a trauma model."

To hear him tell it, Goodwin has endured more than his share of trauma. At Kinkead's restaurant -- where an outwardly calm busboy kept splashing ice water onto the floor in his attempts to fill two glasses -- Goodwin explained that he took the name "Sissy" after being called that as an insult. "It's kind of self-imposed," he said. "Somebody called me sissy one day, and I thought, I guess I am. It signifies what I am, being effeminate. . . . I also hear a lot of faggot' and queer.' "

In any event, Docter said Goodwin's very public brand of transvestism, in which he doesn't seem to be trying to pass as a woman, sounds highly unusual.

"In my opinion he's a very small fraction of 1 percent," Docter said. "If you stood at the Vietnam memorial every single day till next winter and beyond, you might find some other cross-dressers there, but your feet would get cold indeed before you'd find another like him. . . . If this is a man who cannot make it in his appearance as a woman, he may be engaging in a little defensive behavior -- by letting the world see that I am really a veteran and a guy, and I really have nothing to be ashamed of.' "

Goodwin, for his part, said he was born in Casper, the son of a hard-drinking waitress and a harder-drinking oil roughneck who imposed a cruel, nomadic existence on himself and his younger sister. His father's demeaning nickname for him -- which the old man used instead of his given name -- is unprintable in a family newspaper.

After surviving childhood, part of which was spent living in an abandoned railroad car, Goodwin enlisted in the Air Force during Vietnam "because I didn't want to get shot at." But he said he was kicked out early -- although discharged honorably because of an exemplary record -- after a sergeant found him in bed wearing a "frilly blue nightie." He was awakened by the enraged sergeant's terrifying roar: "AIRMAN, WHAT IN THE HELL IS GOING ON HERE?"

After returning from Guam, he tried the rodeo circuit for a while and took courses at the University of Wyoming before settling with his new wife in Douglas and getting a job at the Dave Johnson electrical generating plant operated by Pacific Power and Light. He had told Vickie of his cross-dressing compulsion a few months into their romance.

"I don't recall that it was a crazy shock, but I was surprised," she said. "At the time he was very undercover, so to speak. But as he came out, and became more and more public, it was very difficult for me. It was difficult to understand and to deal with. For a long time I refused to go out with him in public." There were also mounting problems at home and at work. The Goodwins' house was vandalized more than once -- windows shattered with a baseball bat, trees in the front yard uprooted. Once, right in front of his house in Douglas, Goodwin got into a brawl with an abusive stranger who kicked out two front teeth (he now wears a dental bridge). Police officers in both Casper and Laramie, where he would go to shop, arrested him for his cross-dressing, notwithstanding the absence of a law against it. In the mid-1980s, his supervisor at the power plant (where today he often wears a ribbon in his hair) threatened him with dismissal if he didn't change his style.

"That was when I had a nervous breakdown," Goodwin said.

Therapy sessions helped, he said, and the utility workers union protected his job. In the end he received a promotion to the position of control operator -- in charge of one of the plant's powerful turbine generators. He said he earned about $69,000 last year.

"They're used to me now, and I'm accepted," Goodwin said. Officials at the power plant didn't return several phone calls.

These days, Goodwin involves himself in pacifism, politics, cross-dressing. For his 25th wedding anniversary, he renewed his vows with Vickie, inviting 30 friends to witness the ceremony, for which he wore a white satin gown.

He visited the Vietnam memorial this week to see the name of a close high school friend, Army communications specialist Jose Leo Lujan, who died in a helicopter crash during combat in 1968. Goodwin said that when he discovered that Lujan's name was initially omitted from the wall, he toiled for more than a year to push the military bureaucracy to include it. "That was the most unselfish thing I ever did," he said. He returned home yesterday to Douglas, where, he said, he lives happily, occasionally stopping by the College Inn, a bar frequented by bikers, to have a beer. "It takes a real man to walk into the College Inn on a Saturday night wearing a dress," he said. CAPTION: Larry "Sissy" Goodwin on the Mall: "I really love the feel of women's clothes." CAPTION: Sissy Goodwin with wife Vickie in Georgetown, left, and at the Vietnam Veterans Memorial. "We've been together a long time, because I love him," she says.