The drug, called Humatrope, is not for normal kids yearning for a few extra inches, the FDA cautioned. It's for the shortest 1.2% of children.

Maker Eli Lilly & Co. counts some 400,000 such children ages 7 to 15, but predicts that only about 10% ultimately would receive growth hormone because of tight restrictions it plans on eligibility, and because many families simply won't want to endure up to six shots a week for years.

"This is not cosmetic use," stressed David Orloff, the FDA's endocrinology chief.

Also, "this is not saying short stature is a disease," he said. "We are saying that to the extent some of these children and their parents and their doctors feel they would benefit, or they would rather be a little taller than a little shorter, ... the drug does work."

Growth hormone has been used for 16 years to treat children who are extremely short because their bodies don't naturally produce the substance or because of a few other growth-stunting diseases. Some 200,000 children worldwide have taken it.

Lilly sought FDA approval to market formally its brand of growth hormone, Humatrope, for children who don't have those medical conditions but are abnormally short anyway: boys predicted to be shorter than 5-feet, 3-inches as adults, and girls shorter than 4-feet, 11 inches.

The FDA has long fought the continuing problem of cosmetic use of growth hormone and struggled to define just what constituted meaningful, medically appropriate use of the drug without opening floodgates to children of normal height.

Lilly's studies of about 300 children with no known causes of abnormal shortness found regular Humatrope injections provided an extra 1.5 inches to 2.8 inches of height by the time they reached adulthood.

Last month, the agency's scientific advisers agonized over whether the FDA should approve this new use of Humatrope and questioned whether growing those few more inches helped children's quality of life enough to justify spending $10,000 to $25,000 a year for the drug — and getting so many shots.

Ultimately, an impassioned New York teenager persuaded them it did, describing being ostracized in elementary school when she couldn't reach the water fountain and imagining a life too short to even reach a car's pedals. Now 17, the girl's seven years of growth-hormone shots have left her 5-feet-2, 6 inches taller than her doctor predicted she'd ever be.

Some children have more benefit from the shots than others, and there's no way to predict who will benefit more, how quickly they will see growth improvement or even just how many years of therapy children should try, Orloff said.

As part of FDA's consideration, Lilly pledged tight restrictions on Humatrope's availability. Instead of selling it regularly through pharmacies, it can be prescribed only by certain specialists, and will be shipped by specially appointed drug stores to patients who undergo a battery of growth tests.

Also, Lilly cannot advertise this use of growth hormone to the general public.