"I call her 'Puff' because that's what her entry sounds like," says Carl Cox, the coach of Genna Weiss, 10, a diver from Silver Spring, who is so much better than anyone else her age that there doesn't seem to be any comparison. "She's phenomenal. The magic is there."

You expect a bit of hype from a coach, even one such as Cox, who has been teaching kids to flip without flopping for 15 years. But Cox, who also coaches diving and swimming at George Washington University, has more than partiality to back up his opinion.

This summer, at the U.S. National Diving championships in Indianapolis, Weiss beat everyone 10 years and younger in the one-, three- and five-meter competitions. Against girls three years her senior, she placed in the top 10 in all three events. This 4-foot-5 diver who weighs 60 pounds stole the show and made it apparent that she'll be doing a lot more of that in years to come.

"She's doing dives that no other girls her age are even trying," says Margie Weiss, Genna's mother. "Not too many 10-year-olds can even conceive of three twists."

Margie and Greg Weiss are not ordinary "Little League" parents. Gregor Weiss is a former Olympic gymnast and Pan American gold medalist. Margie Weiss was a national collegiate champion in gymnastics and was a member of the U.S. team in 1969. Together, they run one of the most successful gymnastics programs in the country from a Silver Spring home they have built by hand into a sports complex that includes a gymnasium, diving pool, ballet studio and guest house.

So how did they let their daughter Genna, who has the potential talent to be an Olympic gymnast, get out of the gym and into a pool? And why is Geremi, 8, ice skating and Michael, 6, playing soccer?

"I don't want to be their coach," says their father, who at 42 still has the body of a 20-year-old gymnast. "I just want to be their daddy."

The Weiss family couldn't be more all-America if Hollywood had done the casting. Even the way the parents met seems made for prime time. They were working out on opposite sides of the University of Maryland's gym. Margie's mother was having a hard time spotting for her 19-year-old daughter when her future husband offered to help.

"We went out together that same night," says Margie Weiss, now 34. "We both knew within 20 minutes we were going to get married."

Talk to Greg and Margie Weiss for more than a few minutes and the conversation will inevitably cover dedication, self-discipline and the benefits of competition. Their schedules are proof of their sincerity.

"We're lucky that ice skating practice is early in the morning," says Margie Weiss, who shuttles daughter Geremi to a Gaithersburg rink at 5 a.m. six days a week.

Gregor gets the other kids off to school, then heads to Prince George's Community College, where he is a professor of economics. At 1 p.m., Margie Weiss picks up Genna from school for two hours of diving downtown at George Washington University's pool. Both parents get back to Silver Spring just in time to begin coaching their gymnastics team. Michael must get to and from his soccer practice. Genna has two more hours of diving practice at another pool each night. Then there are the competitions that take the Weiss family all over the country and a good part of the world.

"We don't know what it is to sit down for dinner," says Margie Weiss.

"It's good that we're both hyperactive or we'd drive each other crazy," says her husband.

"I can't imagine how they do it. They must collapse every night," says Cox, who has known them four years. He says he is still amazed that two people with such devotion to winning can be so patient with their children and not try to interfere with his coaching.

Cox began coaching diving at the Silver Spring YMCA 15 years ago. In the international scheme of things, that is the baby pool. Since then, Cox has helped a dozen divers achieve national prominence. But the payoff always comes after the divers have graduated from Cox, or been poached by one of the big swimming and diving powers, such as Mission Viejo in California.

"My job is to get other coaches interested in my divers," says Cox, who is thin, curly haired and soft-spoken. "I don't love the sport as much as I love the kids."

But Cox has two divers now who are tempting him to fight the system. Cox thinks Stephanie Willim, 18, a sophomore at GWU, and Genna Weiss are both good enough to be the best. And this time he would like to go along with them for the ride.

Willim is a former nationally prominent gymnast and a student of the Weiss program. Two years ago a congenital spine disorder was discovered, forcing her to quit. She took up diving as a substitute. In two years she has become one of the best in the country.

Genna Weiss has gotten so good so fast, Cox seems both exhilarated and afraid for her future. There are so many things that can happen to a 10-year-old between now and an Olympic gold medal. There are accidents, cookies and boys to avoid. And, sometimes, for no apparent reason, a competitive fire that burned bright in a 10-year-old is barely flickering at 12.

But then Cox looks over at Genna, who is climbing out of the pool after just missing a triple somersault. She is squirting water in two jets between her teeth and looking at her coach with brown eyes that seem too dark for her face.

"Look at the intensity in those eyes. The coolness," whispers Cox. "The magic is there."