When our children were little, my sister and I occasionally would use our own private language around them, a summer-camp lingo we called uppy-duppy. Our parents had a more sophisticated strategy to deal with us: polysyllabic words, telegraphed spelling messages. Their parents in turn had an adults-only language that had been imported from Europe.

What all three generations shared was a desire to keep some information from the young. There were subjects that came with an invisible label: Not in Front of the Children. Sometimes we applied it for their protection, sometimes for our privacy.

There was nothing unusual about us. There have always been ways for an older generation to shut out the younger, to block their access to information, to apply a rating system. Language is one, doors another. Children have been routinely removed from the room during "grown-up conversations" or fights or tears.

But it is different now. Our grandparents had a whole list of taboos: death, sex, c-a-n-c-e-r, m-o-n-e-y. Our own uppy-duppy era was much shorter and less serious. Modern parents, after all, are much more open with their children. Or so we tell ourselves. Still, at times I wonder whether we haven't lost the power to screen the adult world for and from our children.

Last week, a friend tells me, the talk of the second-grade car pool was of Tylenol. The children found out about the cyanide on the evening news. This morning, an eighth-grade teacher calls me in dismay to report the number of her students who have seen "adult" movies on cable TV or videos.

Last month, the space shuttle exploded before thousands of schoolchildren's eyes. No father broke the news, no mother framed the event, no grandparent translated the information. Young and old saw this together. The best that these elders could do was to react, to play catch-up, to help children understand what they had seen.

The adult screen has been virtually wiped out by the television screen.

There is a moment in Joshua Meyrowitz's "No Sense of Place," a striking analysis of television's impact on our culture, when he describes how TV has blurred the lines between childhood and adulthood. "What is revolutionary about television is not that it necessarily gives children 'adult minds,' that it allows the very young child to be 'present' at adult interactions.

"The widespread use of television is equivalent to a broad social decision to allow young children to be present at wars and funerals, courtships and seductions, criminal plots and cocktail parties. . . . (Television) exposes them to many topics and behaviors that adults have spent centuries trying to keep hidden from children." Death, d-i-v-o-r-c-e or, as we say in uppy- duppy, "s-up-ex".

Perhaps the biggest secret that has been blown is about adulthood itself. When Meyrowitz analyzed programs as different as the 1950s' "Leave It to Beaver" and the 1980s' "One Day at a Time," he found something similar: "They both reveal to children the existence of adult weaknesses and doubts."

Television lets children know what we are saying in the other language and what is going on behind the closed door. This exposure, he writes, "undermines both traditional childhood naivet,e and the all-knowing, confident adult role."

In the electronic age, the parent is less of a guide and more of a fellow traveler. We don't slowly expose our children to the world in a series of monitored field trips anymore. We don't control the flow of information into their lives. It comes through a garrulous and permanent guest who doesn't respond to the command, "Shh, the children."

Our own parents, certainly our grandparents, kept too much from us. Many kept themselves from us. As thoroughly modern parents of the electronic age, we comfort ourselves with the notion that we are choosing this "honesty" and, yes, "openness." I just hope that our own children aren't left more v-u-l-n-e-r-a-b-l-e.