Manhasset, New York:  Tom and Allison Penn wanted a baby more than anything. Now they have three, all alike.

The well-behaved triplets, Logan, Eli and Collin Penn, born last week in North Shore University Hospital, faced a battery of TV cameras without a whimper at a news conference at the hospital on Tuesday.

They are identical triplets, the first known to be born on Long Island in almost 15 years. Estimates on the odds of identical triplets being born range from 1 in every 60,000 births to 1 in 200 million births, said Dr Victor Klein, who delivered the three boys.

The babies, developed from a single egg and placenta, were given only a 30 per cent chance of all three surviving by the first obstetrician consulted by the Patchogue couple, said Tom Penn, who called them his "miracle babies".

Klein, who specialises in high-risk deliveries, gave them more confidence. This was his 161st delivery of triplets in 20 years, he said, but none of the previous sets were indisputably identical.

In vitro procedure

The couple, who had been trying for four years to have a baby, opted for an in vitro procedure with Reproductive Specialists of New York, but hoped to avoid multiple births. There was no stopping the embryo from splitting once and then splitting again, however, and now they're happy with their multiple sons, said Penn, 46, a wildlife biologist with the US Fish and Wildlife Service, where his wife, Allison, 31, also works as an environmental educator.

When told they would have triplets, the couple experienced "complete shock. We thought, 'That's not possible'," Allison Penn said. "Then Tom started laughing and I started crying. ... I was terrified."

At the news conference, each wore a dot of nail polish on a different tiny finger so their parents could tell them apart.

The oldest, Logan, has a kidney problem that probably would have "no significance", Klein said.