Katherine Raphaelson adores television.

And up until a few weeks ago, she didn't mind that her 3-year-old seemed to love it, too.

She let him watch two to four hours of television a day, sometimes more.

Raphaelson and her husband, Bill, of Northwest Washington "would sit him down at his little table in front of the TV while we would be in the other room watching the news," Raphaelson says. "He was happy. I was happy."

Then she read about a study published last month in the scientific journal of the American Academy of Pediatrics that linked young children's TV watching with the eventual development of attention-deficit hyperactivity disorder.

These days, you're more likely to find son William listening to CDs than watching "Caillou."

The study, published in the academy's journal, Pediatrics, is the latest salvo in the debates over television and children, and it certainly has caught some parents' attention. Local Internet chat groups have been buzzing about the study, the level of discussion rivaling topics such as lead in the water, schools and affordable child care. And like Raphaelson, some parents have altered their children's TV schedules because of it.

There's certainly been no shortage of studies linking television with violence, obesity and poor performance in school. But this latest hit home in a new way. "ADD and ADHD are the current panic acronyms in the parental landscape," says Marjorie Kaplan, executive vice president and general manager of the Discovery Kids cable channel. "There are so many kids who are diagnosed and parents wondering if their kids have it."

Led by Seattle Children's Hospital pediatrician Dimitri Christakis, the study concluded that for preschoolers, every hour of daily television viewing increases their chances by about 10 percent of developing attention problems later. It also backs up a 1999 recommendation by the AAP that children younger than 2 should not be exposed to television at all.

According to a recent Kaiser Family Foundation report, nearly 60 percent of children younger than 2 watch television on a typical day and about a quarter have a TV in their bedrooms.

"It freaked me out," Alexandria mother Amy Ruby, 29, says of the Pediatrics study. "I never intended to let television raise our child, but it's very easy to let her watch 'Sesame Street' for an hour while I'm doing something else."

Like Raphaelson, Ruby says she's cut her 31/2-year-old daughter Emily's TV time, to an hour a day. "It's forced me to be more creative. She's asking to color and cut [with scissors] more."

But just how much should parents worry?

The scientific community stresses that in no way does the study conclude that TV viewing at an early age causes ADHD.

"It's easy to misinterpret the findings of a study like this and confuse a causal link with an association," says Joshua Sparrow, a psychiatrist with Children's Hospital in Boston. He urges parents to read the study's fine print.

The study itself notes its own limitations, including that existing attention problems could lead to increased television viewing rather than vice versa, and that the home environment in general may have promoted attention problems.

Still, Sparrow understands the strong reaction such a study can provoke from parents who may not want to wait for definitive proof to change their children's TV habits. "If you feel only good can come from altering an environment, you do it," he says.

Sparrow says the study "raises more questions than it answers" and hopes that a more fully funded research project can be conducted.

Those involved directly with children's TV programming have their own questions about the study but don't dismiss the general issue out of hand.

Jennifer Kotler, assistant director for research at Sesame Workshop, which produces "Sesame Street," says the Pediatrics study is making waves partly because not much research has been focused on toddlers. But she remains skeptical.

"It's a good thing people are starting to do more research in the area of very young people from a scientific point of view," Kotler says. "But it's one study and they found a very small link that is correlational" rather than a cause-effect relationship.

The study has also been criticized because it did not consider what kind of programs the toddlers were watching.

But Christakis says the very nature of television, regardless of the content, is filled with "rapid scene changes" that may be rewiring youngsters' brains. "It's an intense level of stimulation," he says. "My concern is that it's deleterious."

Laura Wendt, senior vice president of research for the Nickelodeon network, takes issue with that point. She argues the authors did not take into account the evolution of television designed specifically for preschoolers, pointing out that some of the data collected are fromthe 1980s.

"The commitment to preschool-appropriate television is absolutely a recent phenomenon and it's only getting better," Wendt says.

Nickelodeon-owned Noggin, a network that launched five years ago and is available on digital cable and satellite TV, features shows for young children, such as "Oobi," "Miffy and Friends" and "Maisy," that do not rely on quick editing or fast cuts.

"That's all very preschool-appropriate," Wendt said. "Anything not made for preschoolers is not preschool-appropriate."

Wendt notes that whatever the concerns parents may have, they haven't cut into Noggin's ratings. The numbers for its 2-to-5-year-old viewers in April are equal to or slightly up from last year, Wendt says. "Television can be a great educational tool," Sesame Workshop's Kotler says. "It's really about the content and the way it is used."

Ultimately, however, the choices over children and television remain with parents.

Jennifer Payne, 31, of Silver Spring, read about the study but hasn't changed her 19-month-old son Aidan's TV habits.

"There are some great educational programs," she says. "He learned colors and shapes that I know he picked up from [Nickelodeon's] 'Blue's Clues.' "

Chevy Chase mother Jennifer Loudermilk, 33, allows her two boys to watch one to two hours a day of programming, mainly on PBS and Noggin. "I'm not a big believer that all television is bad," she says. "My husband grew up watching television and he's a Harvard Business School graduate."

Katherine Raphaelson feeds 8-month-old Annie while William, 3, plays with toys in the shadow of the TV. A study linking children's TV watching to attention disorders has prompted her to cut back on William's viewing time.