Marc Jacobs and Underage Models THIS Fashion Week, designers were asked by the industry's leading trade group to redouble their commitment not to use models under the age of 16 on their runways. Valerio Mezzanotti for The New York Times Ondria Hardin at the Marc Jacobs, fall 2012 show. So how did they do? As of Wednesday, most designers said that they and their agents had complied with the health initiative guidelines issued by the Council of Fashion Designers of America by asking models for identification. But there was one notable exception: Marc Jacobs, who knowingly hired two models, Thairine Garcia and Ondria Hardin, believed to be 14 or 15, for his show on Monday. Both girls are represented by Ford Models, which said last week that the company, while in favor of the health initiative, had not agreed to the council's specific proposal of an age requirement for runway modeling. As the industry debates whether designers should be held to regulated standards, one question that continues to challenge them is why they would want to show clothes for adults on children in the first place. And Mr. Jacobs, this season, said he was looking at maturing women whose style has become more flamboyant with age, like those on a blog called Advanced Style. So it was peculiar that he was the one designer standing up for younger models. "I do the show the way I think it should be, and not the way somebody tells me it should be," Mr. Jacobs said. The fashion council, of which Mr. Jacobs is a board member, did not fault him, responding that it is up to the designers to decide whether to follow its guidelines. Mr. Jacobs argued that there are child actors and child models for catalogs, so he did not see an issue here. For decades, many top models have started in their early teens. "There is no controversy," he said. Still, his stance is provocative for a number of reasons, considering his leadership position in New York fashion. Especially so this season, because his models wore enormous Dr. Seuss-style furry hats that pretty much covered their heads. The cleaning staff could have been under those hats, and nobody would have been the wiser.