BALTIMORE, OCT. 31 -- A 4 1/2-month-old baby believed stolen from a Johns Hopkins Hospital bassinet in June and found in Philadelphia on Friday was reunited with his joyous Baltimore parents here tonight after blood tests virtually confirmed that he is their son.

An attorney for the parents said authorities in Philadelphia, where the baby was discovered and his alleged abductor arrested, agreed to release the child after receiving blood test results that firmly indicated he is Kendol B. Kernes.

At a brief news conference here about 9:30 p.m., shortly after FBI agents returned him to his parents, Keith Kernes and Patricia Nixon, Kendol appeared alert and bright eyed. Wearing a red and blue two-piece suit, he cried at first when faced with cameras and lights, but he soon quieted as his mother fed him from a bottle.

FBI agents from the Philadelphia office had met agents from the Baltimore office at a rest stop along I-95 near Wilmington, Del., earlier in the evening, and the Baltimore agents brought Kendol, who had a small bandage on his right arm, to his waiting parents at the bureau's field office in suburban Baltimore.

"If I had to walk I would have gone to get him" once officials agreed to release the child, said Keith Kernes, 23, who added that he recognized his son immediately on television Friday. "He's the spitting image of my other son," Keith Kernes Jr., who is 2.

A smiling Nixon, holding Kendol, said at the news conference that she was "happy" that her long "nightmare" of waiting and wondering was over. Asked about the penalty she would like to see imposed if the woman charged with kidnaping Kendol is convicted, Nixon, 22, said, "Give her the chair."

Added Kernes: "I feel the same way."

The maximum term for a federal kidnaping charge is life in prison.

Also at the news conference was Audrey Kernes, the baby's paternal grandmother, who described being "relieved, very happy, overwhelmed" with the return of the child.

The happy meeting was made possible after FBI agents found the baby apparently unharmed in a seedy shelter for the homeless in southwest Philadelphia and rushed blood samples of the child by air to Johns Hopkins here Friday night.

Agents and local law enforcement officers, working from an anonymous telephone tip, had combed neighborhoods of Baltimore and Philadelphia and tracked down the baby at the church-run Pentecostal Bridegroom Shelter, a facility surrounded by frame houses, topless dance clubs and abandoned cars.

Also at the shelter was Dorothy Jean Brown, a 44-year-old Baltimore Art Museum guard, now being held in Philadelphia on a federal kidnaping charge. Brown's boyfriend, Tony Gilmore, 31, was arrested by Baltimore police Friday and charged with being an accessory.

Brown allegedly fled to Philadelphia last week with an infant she called Tony Gilmore Jr.

Brown, who was born in Philadelphia, used her own name when applying for temporary shelter at the Stenton Emergency Children's Shelter in northwest Philadelphia, according to a child welfare official. Shelter records showed that she was referred to the Bridegroom shelter.

The kidnaping occurred shortly after the abduction of a child from Prince George's Hospital Center in suburban Washington. The two incidents have raised questions about hospital security and the way hospitals establish newborns' identity.

Johns Hopkins officials said today that they have tightened security in their maternity ward and will reestablish a policy of footprinting all infants at birth, a practice abandoned more than 10 years ago as ineffective.

Hopkins doctors also announced results of a blood test comparing a sample taken from the baby found Friday in Philadelphia with a sample the hospital had taken from Kendol Kernes when he was born June 16. That sample, taken routinely at the time, was ordered frozen for possible future comparison after Kendol was kidnaped when he was less than 48 hours old as he lay in a bassinet in his mother's room at the hospital. The mother told police she was asleep when the child disappeared.

Dr. Paul Ness, director of the Hopkins blood bank, said microscopic examination of 15 markers, or characteristics, of the blood in the two samples "matched perfectly . . . . I am very comfortable in saying it is the Kernes baby."

He said chances are "one in a thousand" that the identical samples could come from different babies.

Hopkins performed a second test, called the Human Leucocyte Antigen test, which can match the genetic makeup of a child with the parents' to confirm parentage.

While neither Kendol's mother nor Dorothy Brown has been given this test, Katherine Hopkins, manager of the hospital's immunogenetics laboratory, said, "The chance of both the alleged mothers sharing these antigens is virtually a million to one." It was not known tonight whether Brown or Nixon will be tested.

Dr. Timothy R.B. Johnson, a Hopkins gynecology and obstetrics professor, told reporters that several new security measures have been taken to minimize the chance of kidnapings, including placing more guards at maternity ward entrances and tightening visitor identification requirements.

In the past, visitors simply obtained passes at the main entrance to the hospital and presented them to a security attendant when arriving at the hospital's second-floor maternity ward. Now, Johnson said, visitors must provide photo identification and submit their name so it can be checked against a list of visitors provided by the maternity patient.

FBI spokesman Andy Manning said Kendol Kernes was believed to have been abducted when a woman tricked hospital guards into believing that she was a sister of the child's mother and had come to take Kendol home.

Johnson said hospital security policy has to balance safety with public access, and a hospital should not be "an armed camp."

He said: "Thousands of people pass through this hospital every day," and it is difficult to stop an individual intent on kidnaping. A kidnaping event is very much like a terrorist event. It is very difficult to prevent."

Hopkins spokeswoman Joann Rodgers said the Kernes abduction is the only one in the memory of longtime staff members at the sprawling 98-year-old hospital, a 1,000-bed institution that has 463,000 outpatient visits, 71,000 emergency room visits and 3,000 births each year.

Johnson said Hopkins also plans to reinstitute footprinting to bolster identification of newborn babies. Because of smudging and other problems, the practice was abandoned more than 10 years ago, he said, but improved techniques are now available, and the practice will be resumed.

Brown left Baltimore Sunday, one day before she was scheduled by police for a blood test to prove that the baby was her son.

Philadelphia child-care officials referred Brown to a private shelter at 6901 Woodland Ave. run by the Pentacostal Bridegroom Church. The former Catholic school for wayward girls, located in a run-down southwest Philadelphia neighborhood, was an obscure hiding place for the woman and child. The 165-bed shelter is hidden behind a six-foot-high fence topped with barbed wire, in a neighborhood of working-class frame homes, many of them dilapidated.

The street is occupied by topless dance clubs, fast-food restaurants and small retail shops.

The FBI office in Philadelphia was led to Brown by an anonymous tip after they had already learned that she was from Philadelphia and had relatives in the area. Agents tracked Brown through the Stenton center and then to the shelter to which she and the child had been referred earlier in the week.

A brown, unmarked police car, its red light flashing, stopped in front of the normally quiet shelter about 4 p.m. Friday. Two agents went inside the four-story brown brick building and emerged about 15 minutes later with Brown.

Witnesses on the street said Brown offered no resistance as she was brought to the waiting car. Agents then returned to the building and retrieved the infant, who was in a separate room from Brown in the shelter.

The baby, wrapped in a blue blanket, was taken across town to Children's Hospital of Philadelphia, where he was examined in the emergency room by Dr. Stephen Ludwig, director of emergency medicine.

"The baby was in very good condition," said Bonnie Jacobs, a hospital spokeswoman. "The child obviously was well taken care of."

About an hour later, two FBI agents left the hospital with the infant and placed him in an emergency foster home.

Brown was arraigned on kidnaping charges before a federal magistrate Friday and was being held at the Pennsylvania House of Corrections in Philadelphia. A bond hearing is scheduled Wednesday.