Daniel Greenberg's argument that we're heading for a "glut" in the medical profession [op-ed, Sept. 20] is a matter of debate. One undisputed point that his generalization glosses over is that certain medical specialties are facing shortages.

In pediatrics, for example, we're already experiencing shortages of pediatric specialists in pulmonology, rheumatology, pharmacology, adolescent medicine and certain other disciplines, largely as a result of poor reimbursement for the case of the chronically ill child. Mr. Greenberg's sweeping perspective misses those shortages. But if your own child were severely ill, you certainly would want a physician specially trained in caring for children.

Another implication of this growing shortage may be less obvious: If fewer pediatricians train in subspecialties, the number of qualified researchers goes down as well. In children's teaching hospitals, they are, often, the same doctors. That means fewer researchers pursuing cures for cystic fibrosis, chronic asthma, cancer and more.

A great many of the nation's pediatric specialists are trained at the 59 independent children's hospitals across the nation. But these hospitals themselves are facing a severe economic crunch supporting their training programs because fewer and fewer payers cover the added costs of training. In addition, children's teaching hospitals receive little support for training from the one remaining, significant source of graduate medical education funding -- Medicare -- because they care for children, not the elderly.

JAMES A. STOCKMAN III

Chapel Hill

The writer is president of the American Board of Pediatrics.