Who misrepresented the health of Jessica Katz, the Soviet infant who seemed so desperately to need U.S. medical help?

Her arrival in apparent good health has touched off a debate between some elements of the press, particularly The New York Times, and supporters of the Katz family's efforts to bring her to the United states.

The Times implied today that supporters of the Katz family exaggerated the 13-month-old girl's medical problem to increase pressure on Soviet authorities to allow the family to emigrate.

The Boston doctor who diagnosed Jessica's illness by long-distance telephone countered today that it is The Times and other media that have refused to listen when he and others have described Jessica's improvement from a crisis point last spring.

Dr. Richard Feinbloom said that about two weeks ago, for example, a Times reporter listened while the doctor described Jessica's health and then said, "we don't want to make this look too good or maybe the Soviets won't let them out."

Jessica, her parents, Boris and Natalya, and her 10-day--old sister, Gabriella, arrived in Boston Thursday after the Soviets relented and gave them permission to emigrate.

The Times reported that "the healthy appearance of Jessica at Boston airport Thursday raised some eyebrows." Boston radio stations, The Times added, had broadcast that Jessica would be rushed from the airport to a hospital.

"There was some kind of investment by the media in having a critically ill baby whisked to Children's Hospital," Feinbloom said. He described himself as having been stymied for months by reporters' failure to report Jessica's progress and he is exasperated now to stand accused of the same failure.

"I would just get off the phone with a radio reporter," Feinbloom said in a telephone interview, "and I would hear on the radio that the baby was in critical condition."

Feinbloom said he plans to telephone The Times Monday to request space on the Op-Ed page to discuss media handling of Jessica's case.

Times managing editor Seymour Topping issued a statement today in response to a request for the Times' reply to Feinbloom and others' charges.

"The reporting on this story was meticulous and we stand by it," Topping said.

The Times said Jessica has been in good health "ever since the campaign on the family's behalf began last spring."

Feinbloom and Bert Patkin, whose wife, Judy, was one of the campaign's leaders, both described Jessica's improvement as gradual from a time in April when she was desperately ill.

The improvement came after she started taking a special infant formula -- Pregestimil -- which Feinbloom prescribed after being given descriptions of her condition by telephone from Moscow.

The formula was taken to Moscow a few cans at a time by sympathetic Americans. Judy Patkin, cochairman of Action for Soviet Jewry, took some of the first cans in April.

Feinbloom said that by summer, Jessica's weight and growth began to be almost normal. A few weeks ago, he told Jessica's parents to begin weaning her from the formula and he said today that after examining Jessica for the first time Friday he had decided to accelerate the weaning.

She suffered from malabsorption syndrome, Feinbloom said, but he does not know its cause. Nor can he be certain whether the formula controlled the problem or whether she began taking it at a time when she would have begun to get better anyway. Whether Jessica is cured won't be known until she is fully weaned to ordinary foods.

Patkin acknowledged that some couriers who took formula to Jessica exaggerated her illness because they were unaware of her improvement. People leading the campaign for the Katzes -- who were first refused permission to leave the Soviet Union before Jessica was born -- "were admitting freely that there was improvement," Patkin said. In addition to private citizens, 63 members of Congress petitioned for the Katzes' emigration. Sen. Edward M. Kennedy (D-Mass.) brought back word that they would be released after a meeting with Soviet leader Leonid Brezhnev.