The studies found that the final height of the children exceeded what had been predicted without the drug in a majority of patients, and by as much as four inches in some of those in the second study. The FDA said the drug should be used for only the shortest 1.2 percent of children.

The agency said that "short stature" -- shortness without a clear medical reason to explain it -- is a defined condition, but some do not believe it is a necessarily treatable condition. University of Pennsylvania ethicist Arthur L. Caplan said he was concerned about the FDA approval, because "we will start to treat the normal as a disease." "I think it's dangerous when you take people who are normally short and say there is something wrong with them," he said. "Whenever you take people on the low end of a distribution curve and say they have a disorder, you're starting down a slippery slope."

The FDA decision followed the recommendation of an advisory panel last month that voted 8 to 2 in favor of approving the new usage of the drug. The chairman of the panel, Glenn Braunstein of Cedars-Sinai Medical Center in Los Angeles, said the panel concluded that the drug produced a usually small but discernable increase in height in most patients, and did not appear to cause other health problems. "If a family thinks this will help their child, we concluded they should have the right to use it," Braunstein said. "But it has to be a really considered and informed consent, because the cost is great and the improvement will probably be limited." Braunstein also said that he did not think the drug should be covered by government medical programs or insurance companies unless there is a growth disorder with an identifiable cause. "There will always be someone in the shortest group of a population."