The identical triplets were born Wednesday at North Shore University Hospital on Long Island, New York - an event so rare that an obstetrician estimated it might happen just once in 200 million births.
The triplets' mother, Allison Penn, was impregnated with just one embryo through in-vitro fertilization, said Dr. Victor Klein, a specialist in multiple births and high-risk pregnancies who delivered the boys.
That embryo split in half, and then one half of that split again, he said.
Originally, a doctor told the Penns that it was just too risky to continue.
"The first doctors that we saw, they said that our chances were
dismal, and we should probably just terminate and start over," Allison Penn told CBS News' The Early Show. "I guess some people can reduce, but because they're identical, they were all in one placenta."
"It was either get rid of all of them or keep all of them," she said.
"And there was never a question what we were going to do," added her husband, Tom. "They were happy and healthy right where they were at that time, and there was just no reason to even go that direction," he told The Early Show.
Identical triplets are born at a rate between one in 60,000 and one in 200 million, depending on the research, Klein said.
"This is the first one we're aware of in the literature in the country in which they only put back one embryo" and a woman gave birth to triplets, Klein said. "Most people put back two or three embryos, and you just never know."
Allison Penn, 31, said she and Tom, 46, had tried to have a baby since they got married about four years ago. Although she once thought of having several children, the disappointments over four years revised her dreams downward.
"When it took us so long to get pregnant, I just assumed we were going to have one, and that would probably be it," she said. "So I thought one would be good."
And when she and her husband were told three youngsters were on the way?
"I looked over at Allison and her mouth was wide open and her eyes were like saucers, and she didn't say a word," Tom Penn said. "Then I realized that it was possible, and then I started to laugh."
He confessed he couldn't get over the irony.
"Everything we had done was to have one baby," he said. "Anybody who says God doesn't have a sense of humor - everything we did was just for having one baby, and now we have three."
Allison, an education specialist for the U.S. Fish and Wildlife Service, said she has not decided whether to return to work.
"That's one of those 'one-day-at-time' issues," she said.
To help tell them apart, the boys have a dot of maroon nail polish on their fingers. Logan Thomas has a mark on his thumb; Eli Kirkwood has polish on his forefinger, and Collin McGuire has a mark on his middle finger. Logan may have a problem with a nonfunctioning kidney, but the other children are healthy, doctors said.
Allison's mother has moved in with them and say they are grateful for the support from family and friends.
"So far they sleep a lot," Allison said. "So far."