When 20-month-old Dominic Gasparac began diving underneath the water during his baths, then coming to the surface coughing and choking, his mother decided one thing:

It was time for swim lessons.

Four weeks into water-safety lessons designed for children ages 6 months and older, Brooke Gasparac said her son can now kick in the water and paddle with his arms. During a recent session at the YMCA in Greenfield, Wis., he learned to blow bubbles into the water instead of inhaling it while he plays.

But without yet reaching his second birthday, just how much more should Dominic learn about swimming?

It's a topic hotly debated among experts.

On one side is the American Academy of Pediatrics, which recommends that kids wait until age 4 to learn to swim. On the other are instructors who say that they've taught children as young as 6 months to swim solo — and that they've had great success.

At the YMCA where Dominic and his mother attended class, an instructor led the group in singing "Motorboat, Motorboat," and other rhymes as parents lifted children into and out of the pool then helped them practice skills such as floating on their backs.

The program focuses on getting kids used to the water, not on pushing them to swim independently, said Heather Williams, who leads the group of aquatics directors at the YMCA's seven local pools.

"We can't tell a parent or child exactly when they're going to learn to swim," Williams said. "It's a learning experience in and around the water."

The Red Cross has a similar approach, and doesn't start teaching kids to swim solo until about age 5.

But at Swimtastic Swim School, which has three locations in Wisconsin, instructors teach classes for babies 6 months to 2 years, with the goal that they swim 5 to 10 feet independently by the end of the advanced course.

"We've found great success at teaching infants to swim," said Susan Wainscott, who founded the child-focused swim school. "We just see that the water is so relaxing to the baby, and we see terrific exercise and motor skills being developed at such a young age."

Summer classes at Swimtastic's Waukesha location meet once a week for 30 minutes over an 11-week session and focus on getting babies comfortable with the water.

They learn to hold their breath and let water wash over their faces, then parents and the instructor begin passing the baby short distances in the pool, letting the child go for a few seconds to encourage independent swimming.

Donna Gruman said her two youngest daughters each started classes at Swimtastic when they were 6 months old. Unlike her oldest daughter, who began swimming at age 3 and took six months to be able to put her head beneath the water, the younger children put their heads in the water and blew bubbles after just a week or two, she said.

"If you wait until they're 3, they usually get that fear and they're afraid to get their face wet," Gruman said. "If you start when they're a baby, they don't have that fear. They really take to it."

Still, it's a controversial approach.

How soon is too soon?

According to the American Academy of Pediatrics, kids "are not developmentally ready" to learn swim strokes until their fourth birthday. The group also warns parents not to think kids are safe around water, no matter how many swim lessons they've taken.

And not all great swimmers began early.

Olympic hero Michael Phelps started swimming at 6, as did six-time gold medalist Amy Van Dyken.

But Summer Sanders, who grabbed the nation's attention in the 1992 games, got an earlier start. She began swimming in her family's pool at age 2 and could swim a complete lap in a 25-yard pool by the time she was 3.

Swimmers on the University of Wisconsin-Madison's competitive teams generally learned to swim "before they can remember it," said Geoff Hanson, assistant head coach for the men's and women's teams. But he can't tell the difference between those who learned before age 4 and those who waited.

Still, Hanson recommends teaching kids to swim as soon as they're comfortable in the water — "the earlier the better."

Most parents, though, say safety is their biggest concern, not competitions.

Rob Kopplin said he didn't want his children to repeat a dangerous experience he had as a child. He hopped into a neighbor's pool, thinking he could stand. But the water was over his head and he didn't know how to swim.

His 2-year-old son Elliott, though, has taken to the classes at the YMCA in Greenfield "like a fish," Kopplin said.

Kopplin said he likes the emphasis on safety in his current water lessons.

"It's them getting comfortable, knowing to yell for help, knowing that it's dangerous and respecting that," he said.