Still seeking that perfect gift for a special young girl in your life? Well, look no further than page 50 of the FAO Schwarz 2002 holiday catalogue. For a mere $45, you can surprise and delight her with a Lingerie Barbie.

And what a Barbie Babe she is, decked out in her sexy black (or, if you prefer, pink) garters, stockings and obligatory stiletto heels. Even her PR is PG, giving the phrase "sex toy" a whole new level of meaning: "Barbie exudes a flirtatious attitude in her heavenly merry widow bustier ensemble accented with intricate lace and matching peekaboo peignoir."

Oh darn, reading this too late for holiday gift giving? Not to worry. Mattel plans a February launch for its sixth "limited edition" Lingerie Barbie, promising she'll be "simply sassy in a short pearl-grey satin slip trimmed in black lace" and "thigh-high stockings" that "add a hint of flair."

A middle school principal in New Hampshire first alerted me to Bimbo, uh, Lingerie Barbie (nickname courtesy of a seventh-grade boy who wanted to know, "What's next? 'Playboy Barbie'?"). I've been actively assessing the Lingerie Barbie gasp factor for several weeks now. It's huge. Teachers and parents (even among Barbie fans) can't believe their ears when they hear about this one: Disgusting! How dare they! Don't they have little girls of their own? Where will it all end? Enough!!

Many teens I know, and even younger children, have been equally outraged. High school students at one all-girls school in Tennessee where I recently spoke were moved to start a national letter-writing campaign to chastise Mattel for this brazen sexualization of children.

And girls I know are neither the slightest bit reassured nor deterred by the company's "for age 14 and up" disclaimer. "Get real," said one. "No 14-year-old girl would be caught dead playing with a Barbie Doll, 'lingerie' or otherwise. Who do they think they're kidding?" Said another: "Yeah, right. Maybe they mean 14-year-old boys."

As for Mattel, it seems to be playing peekaboo with its own LB marketing strategy. Says company spokeswoman Ria Freydl, "We're not marketing it to kids," and true enough, the "Barbie Fashion Model Collection" can be found in the more adult-oriented collectible section on Mattel's Web site. And yet, consider this tag line on LB #5's blurb: "Golden hoop earrings and high heels complete this simple but elegant ensemble, perfect for dress-and-play fun!"

"Dress-and-play fun" for adult collectors? I don't think so. At least, I hope not.

And though $45 is more than twice what a parent forks out for the average Barbie, it's still far more affordable (and more child friendly) than most of the other Barbie collectibles found in the Schwarz catalogue and those of other mainstream retailers.

One 10-year-old in my class wasn't buying any of it. He told me last week he'd actually been given one of the dolls by a 5-year-old cousin who had tired of it. "She gives me lots of toys she doesn't want," he said. "Most of them I give to charity. But not this one, no way. I threw it in the river. No child should play with something like that. They'll get all the wrong ideas."

Out of the mouth of babes -- real honest-to-goodness babes, not Barbie Babes. If 10-year-olds are "getting it," maybe, just maybe, the adults out there will begin to see it more clearly, too.

I had begun to wonder what it would take. During the past decade, there have been an unprecedented number of assaults on the whole concept of sexual boundaries (with Lingerie Barbie only of the more egregious examples), typically without so much as a peep from the adult world. Maybe we've just been too busy or too overwhelmed to notice, or perhaps we've become so adjusted to the ever-quickening pace of cultural change that the change itself is simply harder and harder to perceive.

How else to explain the gradual appearance of "soft porn" in perfume and clothing advertisements? How and when did that become "okay"? And when exactly did "fashion" stop being about getting dressed, and start being about getting -- or increasing the chance that you'll soon be getting -- undressed? About the same time, I guess, that Victoria's Secret decided that lingerie (previously thought of as underwear or private wear) was "fashion," too.

Wasn't it only a matter of time before we were treated to a prime-time Victoria's Secret lingerie "fashion show"? And, excuse me, but who was paying attention when the junior streetwalker/sex slave look became the predominant mode of "dress" among teens and even preteens? Or the wide-midriff, belly-button-baring trend for the 7-year-old crowd? Or short shorts, sporting phrases like "Hot Stuff" across the buttocks, for first-graders?

This doesn't seem to faze many adults these days, that's for sure. It was several of my students who drew my attention to a billboard ad for a local day spa: "Ladies Get Undressed!" Actually, it says "Ladies Get Unstressed!," but since the image is of a naked woman lying face down on a massage table, you be the judge. How different is that message from the one delivered by Lingerie Barbie's "peekaboo peignoir"?

You really do have to wonder how we arrived at this point, more than 40 years after the women's movement as well as 20 years and counting into the HIV epidemic. Then again, you might also say, so what else is new. Women are sex objects? Sex sells?

But there's plenty that's new in what's going on in America today. It began in the 1990s with the invention of the "tweens," a marketing niche composed of 8- to 14-year-olds girls and boys, who carry around an estimated $40 billion in their pockets yearly and influence many hundreds of billions more of their parents' buying power. Mattel, which sells about $1.5 billion worth of Barbies every year, is determined to hold onto its share of the tweens. Its brand new Barbie line, out just last month, is aimed at 8- to 12-year-olds. And no wonder: Barbie's biggest fans these days are now between ages 3 and 6. The preteen set, growing up ever so much faster, is a declining Barbie market.

The Mattel solution: "My Scene Barbie," a more "reality-based" doll that a preteen "can really relate to," in the words of company spokeswoman Freydl. See if you can guess the image: If you pictured a sexy, hip, low-rise-jeans-wearing Britney Spears wannabe, you'd be darn close.

This kind of deliberate targeting of younger and younger children and teenagers with sophisticated, adult-oriented messages has been a merchandising coup on a grand scale, and one that promises to keep grown-up "tweens" piling on the profits for decades to come.

It's also been a developmental disaster.

First of all, you'd have to be suspicious of anyone who wants to lump together 8-year-olds and 14-year-olds. Now hear this: Children are not preteens, preteens are not teens, and teens are not adults.

Of all the lines that have been blurred in our culture over the past 10 years or so, none is more dangerous (and sad) than this one. And it would be equally dangerous to chalk up this concern, as some do, to prudery or "the generation gap" or encroaching conservatism. What's going on here is nothing less than the violation of our children's most fundamental rights and needs.

A sense of clear limits is not just "nice" for children and teens, it's almost as important to them as oxygen. Limits and boundaries -- those brackets we put around our children's lives to keep them safe and healthy -- do for them what they are not yet able to do for themselves. A culture that screams "There are no limits!" at every turn puts children in great peril.

Those of us in the business of education have been worried about middle- and high-school students for a while. The stories of the past few years are harrowing: Oral sex in middle-school buildings; boys making videotapes of their sexual exploits -- without the knowledge or consent of their partners -- and showing them off; boys distributing, via the Internet, the names and telephone numbers of girls, along with how much they are known to "put out" sexually, and defending themselves by saying it's all in the name of fun; girls taking sexually provocative pictures of themselves and posting them on their Web sites; girls and boys speaking, dancing and moving in sexually explicit ways during skits in front of all-school gatherings, even with young children present.

The litany of stories I'm hearing now involving young children are even more disturbing: "freak" dancing or "grinding" at fifth-grade graduation parties in public school buildings, with adults as passive onlookers; 8-year-olds being taken to see R-rated movies such as "American Pie II"; elementary school children posting sexual jokes and messages online, even on school networks; mothers finding pornographic passages in their fifth-grade daughters' diaries; fourth-grade boys turning to fourth-grade girls in the cafeteria line and asking, "Do you spit or swallow?"

In many of these situations, it is clear that adults are complicit, either by their neglect, cluelessness or even subtle, if not direct, encouragement. Perhaps we adults, too, are being hoodwinked by the tweens marketing blitz. We conclude that children who look, dress and act older are actually more mature. We're fooling ourselves, and our children.

Some blame "the media," but that's way too easy on parents. One mom at a talk I gave recently complained that she'd wanted her husband to attend but he begged off, saying he was "just too uncomfortable" to talk to the kids about sex. I tried to advise her, but gave up and said (in a nicer way): Go home and tell him to grow up.

If we're uncomfortable, we need to get over it. If we don't know what to say, or how and when to say it, we need to figure it out. If we're feeling overwhelmed in the face of an all-powerful popular and youth culture, we need to reach out and work with other parents to reassert our rightful authority and responsibility for our children's well-being. And we'll need to begin at younger ages than we ever may have dreamed.

Ultimately, we'll need to create a society where our children's first and most important reference points about sexuality are families and schools, not their peers, the media or the Mattel company.

Let's start by heeding the uncommon wisdom of my 10-year-old friend: Not this one, no way. Deborah Roffman teaches human sexuality at the Park School of Baltimore. She is the author of "Sex and Sensibility: The Thinking Parent's Guide to Talking Sense About Sex" (Perseus Books).