Last week an unmarried California couple decried a hospital's rejection of their dying infant as a heart-transplant candidate on grounds they might not be able to care adequately for the child. Today, the hospital's initial decision appeared to be the best thing ever to happen to 16-day-old Jesse Dean Sepulveda and his parents.

National television coverage of the dispute between the couple, Jesse Sepulveda and Deana Binkley, and Loma Linda University Medical Center, the only U.S. hospital with any significant success in infant heart transplants, alerted a Michigan couple to Baby Jesse's plight. In an emotional call today to his parents, who were in New York for a taping of the "Donahue" TV show, a spokeswoman for Deborah Walters and Frank Clemenshaw of Wyoming, Mich., offered Jesse the heart of their 16-day-old son, Frank Edward Clemenshaw IV, who was declared brain dead last week.

Frank, who was placed on life-support systems after his birth May 25, was flown to California for the transplant surgery, which began about 6 p.m. (9 p.m. EDT). The operation was expected to take several hours.

Late last week, Jesse's paternal grandparents assumed custody of him, and doctors at Loma Linda reversed themselves and agreed to a transplant if a donor could be found. The hospital had originally balked at helping a baby whose family situation might impede recovery and thus waste a difficult-to-find donor heart.

Gera Witte, a spokeswoman for Butterworth Hospital in Grand Rapids, Mich., said the publicity in Jesse's case "definitely had an influence" on the decision of Walters and Clemenshaw to donate the heart of their son. The baby's umbilical cord was pinched shut during labor, cutting off oxygen to his brain. Hospital officials had asked the parents if the baby's organs could be used for transplants.

"They waffled. They didn't know what they wanted to do," Witte said. Then they saw a televised report on Jesse over the weekend and returned Monday to say "they wanted to help that baby," Witte added. Loma Linda was immediately informed and sent a team to Michigan this morning.

Walters and Clemenshaw told a Grand Rapids news conference today that they identified with the California couple, unmarried like themselves and who, Walters said, "maybe were going to lose a child. It's a very hard thing to do, to watch a baby die."

Walters said that if the transplant were successful, she hoped to be kept informed of Jesse's progress "because then part of my son will be living in him."

Four successful heart transplants have been performed at Loma Linda by a team led by Dr. Leonard Bailey, who became noted in 1984 for attempting to save Baby Fae, an infant with the same hypoplastic left heart syndrome suffered by Jesse, by giving her the heart of a small baboon. The operation sparked national controversy, particularly after the baby died. Bailey said he would put off further experiments until the results had been completely evaluated.

He said then that he had been forced to try baboon hearts because so few human infant hearts were available. But on Nov. 20, 1985, a donor heart was found and transplanted into another patient with the deformity, which usually brings death quickly if untreated. That patient and three subsequent transplant recipients have returned home and seem in good condition, a Loma Linda spokeswoman said.

At a news conference this afternoon, Bailey said that at least 20 babies with hypoplastic left heart syndrome have been referred to the hospital since 1984, but that he has been able to help only a few, again because of the scarcity of donors.