Back when I was growing up, we had only one television. My parents were relatively prosperous, so they could certainly have afforded another set, but it simply wasn't done. The television was in the recreation room, not far from the fireplace, and we'd gather as a family to watch Ozzie and Harriet and Sergeant Bilko, who sent my father into paroxysms of laughter.

We had a stereo set in the living room, and I had a radio in my bedroom. I was an avid newspaper and magazine reader, but that was the extent of my exposure to what is now known as the media. During the school year, TV exposure was perhaps three or four hours a week, and the most violent thing I remember seeing was Edward R. Murrow's classic documentary on migrant workers.

In just one generation, the media have invaded the realm of childhood like the Kurgan horsemen pouring out of the central Russian steppes into ancient Europe. The Kurgans are believed to have made three major incursions, beginning in 4300 B.C. and ending in 2800 B.C. The media have also made three major incursions: television, video games and computers -- and they have forever changed the magic of childhood. Imagination is no longer the ticket to entertainment and to dreams: The on-off button is. Our own memories of childhood amusements and learning are probably completely irrelevant to the world of children today.

The Kaiser Family Foundation, in a new report on children and the media, put it this way: "While one generation of Americans experienced a childhood in which they shared a single black and white, three channel TV with their parents, the next is growing up with a Walkman glued to their ears, 100 channels in the bedroom, and a World Wide Web of information at their fingertips. One generation may have flinched at gunshots in a western; the next generation plays video games with violence so vivid it leaves them ducking to avoid being splattered."

The Kaiser study examined how 3,000 children ages 2 to 18 choose and interact with the whole array of media that is now available to them: TV, radio, movies, computers, music, video games, magazines, books and newspapers. The findings, released last week, provide one of the most comprehensive overviews to date of children's use of the media. The average child is growing up in a home with three TVs, three tape players, three radios, two VCRs, two CD players, one video game player and one computer. Schoolwork, anyone?

There are some surprises: Children don't spend nearly as much time with computers as Bill Gates would like us to believe, although if forced to choose between computers and TV, most would opt for the computer. Yet it is the television that they spend the most time with now. In many of the homes, the TV is left on much of the day. Among children 8 years and older, two-thirds say the TV is usually on during meals. So much for quiet family gatherings when people can share the events of the day.

After dinner, these children retire to bedrooms that are their own media centers: More than half of all children have a radio, tape player, TV or CD player in the bedroom. A third have a video game, almost a third have a VCR, and more than one in seven have a computer. Among children 8 years and older, 65 percent have TVs and one in five has a computer. A third of children ages 2 to 7 have TVs in their bedrooms. Parents reported that these young children spend more than three hours watching TV on an average day.

Half of all the children say they have no rules about what they can watch on TV or how much they can watch. TV is the universal babysitter: Ninety-five percent of the children over 7 years of age watch TV by themselves.

Children's use of media peaks from the age of 8 to 13: They spend 6 hours and 45 minutes of every day with some kind of media. More than one-quarter spend more than five hours a day watching TV. Only 5 percent spend more than an hour online. Attention, Steve Case: This is an amazingly undertapped market. Actually, children of all ages are an undertapped market: They spend about a half-hour a day using computers, and that includes the time spent using them in school.

Television remains the dominant media force in children's lives, with two-thirds reporting that they spend more than an hour a day watching TV and 17 percent saying they spend more than five hours a day watching TV. But there is some better news than people might have anticipated in children's electronically wired lives: Kids spent nearly three-quarters of an hour a day reading for pleasure.

The most dismaying finding of this latest study is the amount of unsupervised television watching. Clearly, parents need to be more involved in choosing what children watch and when. And the study contains a finding that should finally give some motivation to parents who can't be bothered with doing this. The study found that children who use the media the most tend to be the least contented. The study found that such measures of discontent as not getting along with parents, unhappiness at school and getting into trouble in school "are strongly associated with high media use."

A decade ago, the National Assessment of Educational Progress found that the top 10 states in math proficiency were also the states that reported the least time children spent watching TV. It also found that the states where children watched the most TV had the lowest math proficiency. The Kaiser study also found that children with A's and B's spent more time reading and less time with other media. The verdict couldn't be clearer about the impact of too much TV.

It doesn't take a genius to figure out which way families should be going when it comes to influencing their children's use of media. The message from this study is clear: Take the TV out of the bedroom and put in a bookcase.