Some day the Joffrey Ballet may give a press conference to introduce a promising young dancer named Ronald Reagan. But not yet -- not until after the Republican convention, according to Reagan campaign officials.

The candidate's youngest son was scheduled to meet with reporters yesterday morning. But the event was abruptly canceled at the request of Reagan campaign headquarters. The press conference had been called by Sally Bliss, director of New York's Joffrey II ballet company -- for which young Reagan has been dancing on tour -- in response to rapidly escalating inquires from news media.

"We were getting literally a call a minute from the press of the world, and we weren't able to get our work done." Bliss said yesterday. "I thought a press conference would be an opportunity to explain what Joffrey II is and then get one with our work."

She said that she had discussed the idea first with young Reagan, and that he thought it was a fine idea. He then checked with his parents and reported back: "They said I can do anything I want."

After the conference had been arranged, Bliss said, "The head of the Reagan campaign called and asked us to postpone it until after the Republican convention."

"We're not trying to hide the kid," an official on Reagan's staff said Yesterday. But "the kid" -- the youngest of Reagan's four children, who quit Yale after his freshman year to become a ballet dancer -- was effectively hidden yesterday. Reporters had been invited to City Center in New York, headquarters of the Joffrey Ballet, to talk to the 22-year-old dancer. But those who showed up were stopped in the lobby of the building and told that the conference had been canceled at the suggestion of Reagan campaign headquarters.

Reached at the headquarters, a campaign official said the explanation was that Reagan's staff left that the candidate's son -- who is young and inexperienced in dealing with the press -- should not be exposed to a press conference without preparation and technical assistance. "The kid's all alone back there," said a Reagan aide, adding that he might talk to the press "after the Republican convention."

References to the candidate's son have been appearing with increasing frequency -- not so much because of his career choice, but because his parents sometimes have appeared a bit uncomfortable about it. In working on her autobiography, Nancy Reagan reportedly struck out a phrase describing young Reagan's dance career and decided instead that he should be described simply as "artistic." And when the elder Reagan is asked about his son, he often explains that the young man's urge to dance began as an athletic impulse, that he began dancing as a calisthenic exercise when he was a high-school basketball player, and then "it took hold."

In an article in the coming August issue of Playboy, author Robert Scheer says that "The Reagan children are an embarrassment to the campaign precisely because they are interesting" and suggested that "Maybe it doesn't fit Reagan's high-in-the-saddle image to have a son who's a ballet dancer."

Right now, young Reagan is still learning his craft, but according to Bliss he may have a promising career ahead. She said that the program in which he is now involved is aimed at training solo dancers for the parent company, and three-quarters of the solo dancers in the first company are alumni of Joffrey II. The second company, formed 10 years ago, is "like a farm team" for the main company, she said. It developes choreographers as well as dancers, and two ballets that originated with Joffrey II were later adopted by the main company.

Bliss said that the candidate's son is "extremely talented and very intelligent. His mind is working in the right direction, and he works hard. I can't imagine that he won't be a great success in his chosen field."

She also dealt with the ticklish question of image that may influence many American's image of male ballet dancers: "All the boys in my company are straight," she said, "and Ron has a wonderful girlfriend."