In a New York Times article titled “When Is Thin Too Thin?“, Eric Wilson writes about a September 2006 fashion show at which the models:

appeared so gaunt and thin that their knees and elbows were larger than their concave thighs and pipe cleaner arms, and their bobbling heads looked as if a slight breeze could detach them from their frail bodies.

He reports that questions have arisen about the degree to which designers are contributing to the trend. Even though such criticism has led to some increased visibility for images of women who are not so thin, in the initial fashion roll-outs, ultra-thin is the norm. And designers remain resistant to pressure to change:

The producers of these fashion events have largely dismissed the concerns. On Saturday a British cabinet member, Culture Secretary Tessa Jowell, called for London designers to follow the example of Madrid by banning underweight models. But the British Fashion Council, led by Stuart Rose, the chief executive of Marks & Spencer, said it would not interfere with the designers’ aesthetic. And some designers said it was misleading to equate thinness with being unhealthy and that the standard cited by the organizers in Madrid did not take into account age and puberty, which may cause a model who is unusually tall to appear frighteningly thin.

Wilson summarizes the Madrid decision to mandate against ultra-thinness this way:

Last week the organizers of Madrid fashion week, usually an overlooked event in comparison with the major shows in New York, London (this week), Milan and Paris, said they were banning models with a height-to-weight ratio below what the World Health Organization considered normal. In effect, models who weigh less than 125 pounds are prohibited from working the runways. Organizers of the event said they wanted to project “an image of beauty and health.”

Reports on the Madrid decision are available here (CNN: “Skinny Models Banned from Catwalk”) and here (BBC: ” Madrid bans waifs from catwalks”).