The Ringling Bros, and Barnum & Bailey Circus is perhaps the largest if not necessarily the most sentimental extended family on earth. Yet some 100 troupers stood by with misty eyes when 19-year-old Dolly Jean Jacobs auditioned one afternoon in Washington last spring, swooping from the Roman rings 32 feet above the floor—without a safety net. Her dad, Dolly says justifiably, "is the circus." Lou Jacobs, a 53-year veteran at 74, is the reigning king of clowns whose tomato-nosed portrait was chosen for the 5¢ U.S. stamp commemorating the Ringling circus in 1966. Dolly's mom, Jean Rockwell Jacobs, 54, was a New York fashion model who impulsively decided to join the circus and, on her eighth week as an aerialist in 1948, crashed 50 feet to the floor of the old Madison Square Garden. She was in a cast for three years and, against all doctors' prognoses, is walking again.

Entering the family business may be anathema to her generation, but Dolly became a Ringling Bros, show girl at 13. She later dropped out to train for three months with her godparents, Margie and Joe Geiger. (Joe is one of the few survivors of the legendary Flying Wallendas.) Dolly's goal was to recreate an "esteemed empyrean" (in the hyperbole of the ringmaster) gymnastic ballet that had not been brought off in decades. Impresario Irvin Feld was so enthused about Dolly's now famous try-out in Washington that he hired her to premiere that night.

Now, at 20, Dolly is one of the youngest and one of the few American stars of the 107th edition of the Ringling Bros, tour. "We always loved the circus and dreamed of being in it," says Dolly, speaking also for her older sister, now a trapezist for a lesser U.S. troupe. "But Papa insisted we stay at home with mother in Sarasota," she recalls. "I never really liked school. I was kind of an outsider, because I was with the circus." Jacobs finally relented, and the family joined him in a stateroom on the circus train while the girls finished high school through correspondence courses and worked part-time as show girls. Jacobs says defensively, "I left them often enough to realize that I wanted the whole family together, but I didn't push the circus."

On the road, Dolly lives on the circus train in a compartment next to her parents with a parrot and Belinka, a puppy of Jacobs' famed show dog Knucklehead. She shuns riding the train from city to city, preferring her recently purchased Toyota. At night she does the cooking for her parents. "Mom did her time," she says. "Now it's my turn to take care of them. Most nights I do German dishes for Papa." (He was born there.)

Dolly had a thing a few years ago with a Bulgarian performer (she's fluent in the language), but currently she doesn't date, much to her father's relief. She doubts it would be a circus person anyway. "My stakes are high," she explains. "Besides, most of the guys around here you wouldn't take a second look at."

Jacobs can't seem to praise Dolly to her face, but standing in the wings watching his daughter work, he says quietly to a stagehand, "She's a terrific performer. I won't have to work much longer." Dolly's mom, who now runs a circus concession souvenir stand, steers clear of the big top while Dolly is on. "I'm a typical mother. If I know she's having difficulties, I don't want to watch. But I'm proud of her," she says. "I was never that good. Every generation gets better. I'm just glad when the music is over and I know she's all right."