LITTLE HOTTIES.

Barbie is forty-seven years old, and forty-seven years is a long time to have been the alpha doll. Over the decades, many competitors have been sent out into the world to get what Mattel's doll had: hugely profitable sovereignty over the imaginations of little girls. Some of these rivals briefly grabbed a small share of the fashion-doll market. The Tammy doll, which had a wholesome teen-aged look and came encumbered with parents, stuck around from 1962 to 1966, before Barbie squashed her flat. In 1969, Ideal Toy created Crissy, whose hair grew with the push of a button; you can still find Crissy on eBay, but not in Toys R Us. Kenner's spookily big-headed Blythe, whose eye color could be changed from green to blue to pink to orange, lasted for one year: 1972. (She has since been rediscovered by hipster collectors; a photographer named Gina Garan poses her in myriad scenarios, as if she were a plastic Cindy Sherman.) In the mid-eighties, Hasbro launched Jem--corporate by day, rock and roll by night. Mattel moved swiftly to undercut her with its own Rock Star Barbie. And then there were the earnest attempts to make more "realistic" fashion dolls, an enterprise doomed to oxymoronic failure. The Happy to Be Me doll, which came out in the early nineties, when childhood anorexia was a bigger media trope than childhood obesity, had a thicker waist, wider hips, and larger feet than Barbie, and left little girls cold. As M. G. Lord, the author of "Forever Barbie" (1994), wrote, "She may have been happy to be herself, but it was obvious, even to kids, that she had extremely low standards." And the Get Real Girls--muscular, sporty dolls who were supposed to be snowboarders, soccer players, and the like--might have appealed to athletic girls, except that athletic girls preferred to play sports. "They can kick Barbie's butt like you wouldn't believe," a promotional Web site promised in 2000. On store shelves, though, Barbie kicked theirs.

In June, 2001, M.G.A. Entertainment, a small toy company in Southern California, unveiled a line of dolls called Bratz. It was not an auspicious debut. M.G.A. had enjoyed some success with handheld electronic toys imported from Japan--M.G.A. stands for Micro Games of America--and with a baby doll called Singing Bouncy Baby, but never with a fashion doll. The company was privately owned, and its headquarters were in a drab stretch of the San Fernando Valley, amid a jumble of taquerias and doughnut shops near the Van Nuys airport. Its C.E.O., Isaac Larian, an Iranian immigrant with a degree in civil engineering whose first company imported brass tchotchkes from South Korea, still made sales calls himself. When a doll designer and on-and-off-again Mattel employee named Carter Bryant brought Larian a drawing of a new doll he had in mind, Larian at first saw little to admire. "To be honest, to me it looked weird--it looked ugly," Larian told me. But Larian's attitude toward the tastes of children is respectful to the point of reverence, and his daughter Jasmin, then eleven years old, happened to be hanging out in his office that day. Larian asked her what she thought of the drawing. "And, you know, I saw this sparkle that you see in kids' eyes," he recalled. "They talk with their body language more than their voice. And she says, 'Yeah, it's cute.' " For Larian, that was enough: "I said, 'O.K., we'll do it.' "

At first, M.G.A. struggled to give Bryant's drawings three-dimensional form. The design showed a face in which the lips and eyes were cartoonishly prominent and the nose was vanishingly small: it was as if the doll had undergone successive rounds of plastic surgery. Molding that micronose in vinyl wasn't easy. At the Hong Kong toy fair in January, 2001, Larian and his team had only a rough sample to show venders; the hair was Scotch-taped on. And in October of that year Toys R Us cancelled its order for Bratz because initial sales were not what Larian had predicted. He borrowed money to fund more advertising; by Christmas, Bratz dolls had taken off.

In the five years since then, M.G.A. has sold a hundred and twenty-five million Bratz worldwide, and it has become the top fashion doll in the United Kingdom and Australia. Global sales of Bratz products reached two billion dollars in 2005; sales of Barbie remained higher, at three billion dollars, but they declined by 12.8 per cent. Last December, after five years in which domestic Barbie sales had either declined or stagnated for all but three quarters, Mattel replaced Matthew Bousquette, who had headed the Barbie line, with Neil Friedman and Chuck Scothon, who together had been running its successful Fisher-Price division. (Friedman, a president at Mattel, is known to be gifted at turning around flagging toy lines.) According to Sean McGowan, a toy-industry analyst at Wedbush Morgan Securities, Bratz has now captured about forty per cent of the fashion-doll market, compared with Barbie's sixty per cent. Barbie is still an instantly recognizable brand name, like Kleenex or Coke, but even Scothon says, "The competition has changed. There's no denying that."

Bratz dolls have large heads and skinny bodies; their almond-shaped eyes are tilted upward at the edges and adorned with thick crescents of eyeshadow, and their lips are lush and pillowy, glossed to a candy-apple sheen and rimmed with dark lip liner. They look like pole dancers on their way to work at a gentlemen's club. Unlike Barbie, they can stand unassisted. I've heard mothers say that they would never buy their daughters a doll that couldn't stand on its own, but perhaps they should have been more careful what they wished for. To change a Bratz doll's shoes, you have to snap off its feet at the ankles. (It's creepy but ingenious; because the footwear is attached to the legs, all those little shoes are harder to lose.) Their outsized feet are oddly insinuating: you can picture the Bratz dolls tottering around on their stalklike legs, like fauns waking up from a tranquillizer dart. Bratz dolls don't have Barbie's pinup-girl measurements--they're not as busty and they're shorter. But their outfits include halter tops, faux-fur armlets, and ankle-laced stiletto sandals, and they wear the sly, dozy expression of a party girl after one too many mojitos. They are the "girls with a passion for fashion," as the slogan has it, so their adventures--as presented in all those "sold separately" books and other paraphernalia--run to all-night mall parties and…