Originally Posted by Boston Globe

Inside the dressing room at Ann Taylor, Wendy Chao found herself at a loss.

''I tried on a size 0 skirt and it was too big," said Chao, a 30-year-old graduate student of molecular biology at Harvard University. ''To me, a size 0 is antimatter; it's something devoid of any physical reality."

Chao was already mystified by how she'd shrunk from a size 8 in high school to a size 2 today, despite gaining 15 pounds in the interim. But now at size 0, she realized something curious was afoot.

''As far as I can see, size means nothing," she said. ''I am different sizes at different stores, but they're all remarkably smaller than what I wore as a scrawny teenager. In my closet, I have everything from a size 0 to a size 12." She added that a size 8 skirt she bought from Ann Taylor in 2000 is ''identical in cut" to the size 0 she bought at the store late last year.

The incongruity in Chao's closet is far from a fluke: While Americans have statistically gotten larger, women's clothing has gotten smaller -- that is, if the numbers on the size labels are to be believed. It's no secret that retailers have been playing to women's vanity for years by downsizing the sizes on garment labels, but the practice has reached an extreme in recent months with the introduction of the sizes ''double zero" and ''extra, extra small." If vanity sizing continues on this path, analysts say, it is only a matter of time before clothing sizes are available in negative integers.

In many ways we're already there, said Bridgette Raes, an image and style consultant in New York who notes that the sizes double zero and extra, extra small available at stores like Banana Republic and Old Navy are essentially negative sizes. Instead of putting a -2 size on the label, manufacturers use 00, which is the same thing.

J. Jill introduced its ''extra, extra small" size last year in response to its petite customers' demands for smaller sizes, said Lauren Cooke, a public relations manager for the company.

''We've always had size 'extra small,' but our clothing tends to be cut more generously because we cater to women over 35," she said, noting that an extra small at J. Jill is the equivalent of a size 2 or 4 at other stores. Their extra, extra small is equivalent to a size 0.

The downward evolution of sizes illustrates the extent to which retailers, apparel manufacturers, and designers are conforming to American women's obsession with wanting to be thin -- even if it's only in their minds, said Natalie Weathers, an assistant professor of fashion industry management at Philadelphia University.

In addition, the small sizes help retailers attract the junior-sized buyers -- typically girls in their teens -- to adult stores.

Vanity sizing has been a common practice in expensive women's clothing for decades, but Weathers said the practice has crept into the mass market because a wider spectrum of women -- teenagers through baby boomers -- are more preoccupied with size than ever before.

''We live in a world now where 14-year-olds shop at Victoria's Secret," said Weathers. ''On the other side, we're always hearing how 50 is the new 30."

And the gap between what's reality for most women and fantasy also seems to be bigger. While more than 60 percent of American women are overweight, women on television and on the big screen are getting skinnier and skinnier. In fact, after producers of ''Desperate Housewives" learned their star Eva Longoria is a size 00, they wrote a reference to her clothing size into an episode.

While images of Hollywood certainly feed the frenzy, there are other factors at work, said April Ainsworth, owner of VintageVixen.com, an online vintage clothing retailer. With some exceptions, manufacturers are simply making women's clothing larger and labeling them with smaller sizes. As a result, what was a size 8 in the 1950s had become a 4 by the 1970s and 00 today. The size labels just keep getting smaller, so it's no surprise they're diving below zero now, Ainsworth said.

If this trend continues, some petite women may find their own shopping options limited as the smaller sizes available at some of their favorite stores actually become too large for them.

Just ask Kelly O'Rourke, 27, of Roslindale. She loved shopping at such stores as Ann Taylor, the Gap, and J. Crew because their petite lines were cut to her silhouette. However, she said she recently found that sizes 0 and 2 are too big for her at some of these retailers.

''It's frustrating to me as a petite woman when I try on a size 2 suit and it's swimming on me because it really has the measurements of a size 6," she said.

The picture is further complicated by the fact that sizing varies among brands and stores, making it difficult for many women to know exactly what size they are. The problem has only become more acute since January 1983 when the US Department of Commerce dropped a uniform sizing system for women on the grounds that it no longer reflected the size and shape of the average consumer.

''Sizing has always shifted to match consumers' changing behaviors," said Kathleen Fassanella, a pattern maker and author who writes an apparel manufacturing blog called Fashion Incubator.

''For instance, when women stopped wearing corsets, manufacturers had to completely redesign their patterns due to the great dissatisfaction of women who were no longer wearing the undergarments."

But because women have gotten larger, Fassanella said, their clothing is cut larger today -- though many of the labels won't tell you that.