The wedding dress that Kate Middleton wore when she married Prince William went on display at London’s Buckingham Palace last week and is expected to attract more than 650,000 people during its exhibition. Reporters who have seen the dress in person consistently note how small it is; ABC News’ Nick Watt called it “teeny, teeny, tiny.”

In the weeks after the royal wedding, photos of the size 0 duchess appeared on the covers of nearly every popular interest, celebrity and entertainment magazine — along with dozens of special collector’s edition issues and specials devoted just to the wedding, spilling with photo after photo of the bride.

For months, the news media and the public have swooned over how beautiful and fairy-tale perfect the bride was. Amid all the pomp and celebration, one of the darker aspects to the wedding was how thin she was too.

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According to one ABC News story, “A radiant, but wisp-thin Kate Middleton stepped into the public eye. … The lace-bodice dress, designed by Alexander McQueen’s Sarah Burton, clung gracefully to her lean frame, possibly adding to questions about the newly titled Duchess of Cambridge’s health.”

Photos of the beautiful bride in her dress continue to appear in magazines long after the wedding; she’s even on the cover of this month’s People magazine. Star magazine noted that Middleton “has gone from fit and toned to gaunt and bony,” and her “unbelievably frail frame is sparking fears that she may be anorexic.”

Middleton, who is reported to be about 5 feet, 10 inches, and 100 pounds, would have a BMI of less than 14. Anyone with a BMI under 18.5 is considered clinically underweight.

While Kate may be unhealthily thin, some researchers are concerned less with her personal weight than with her influence on young women’s body image issues and eating disorders. Last year, British Equalities Minister Lynne Featherstone championed a campaign against photos of thin women because of the "dreadful pressure that young people, girls and women come under to conform to completely unachievable body stereotypes.”

Could the beautiful and “wisp-thin” Middleton “encourage” anorexia in hundreds of thousands, or even millions, of women? That’s what Featherstone and many others believe. A similar fear was expressed when the thriller Black Swan premiered; I wrote about this in December 2010:

The new thriller

As noted in the original piece, it seems unlikely that many women would see the troubled fictional ballerinas in Black Swan as people they idolize or aspire to be like.

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Kate Middleton, on the other hand, is a very different story; she’s the real-life, beautiful, charismatic bride who married a prince. The royal wedding was seen by more than 20 million Americans and more than a billion people around the world. It seems far more likely that future princess Middleton would be seen as a role model than a mentally unstable fictional ballerina in a thriller (or a thin sitcom actress or movie star).

There is some question about whether most ordinary women truly aspire to be thin as fashion models, but there can be no doubt that huge numbers of them are specifically wanting to look like Middleton — especially on their wedding day.

Middleton is far thinner than the average woman, thinner than the average pop star or actress, and would be considered just as “unrealistically thin” as the oft-vilified fashion models or Barbie dolls. Kate’s body is what Minister Featherstone claimed was dangerous to young women: a beautiful, very thin ideal that the average woman has no hope of achieving.

It’s unlikely that there has been a thinner, more widely adored and photographed, and higher-profile female. Middleton would be the "perfect storm" of influences and conditions that, if Featherstone and others are right, leads to widespread body dissatisfaction and/or eating disorders among women in the coming months and years.

In fact, the link between images of thin women and eating disorders is widely assumed yet remains unproven. Studies show that teen girls' friends and peers have much more influence over how they feel about their bodies than do fashion models, and the majority of girls report being happy with their bodies.

Still, the debate rages on, and this will be a real-life test of that hypothesis: If thin, beautiful celebrities and fashion models cause anorexia, as is widely claimed, there’s good reason to expect that the royal wedding will spur a surge in eating disorders among women around the world.

On the other hand, if thin actresses and models do not have as much power and influence over young women as widely assumed, the countless images of the beautiful, wisp-thin princess-to-be will have little effect. Time will tell.