New Zealand's estimated 3200 leapers are set to celebrate their first official birthday in four years.
Statistics show the chances of being born on February 29 are one in 1461.
Claudia Aroa and her daughter Larree, both from Tauranga, defy the odds even further by sharing the same leap year birthday. There is a one in 2,134,521 chance of a mother and her child sharing February 29 as a birthday.
Claudia will turn 76 a week on Monday but will be just 19 in leap year terms. Larree will be 52, or 13, depending on which way you look at it.
The Aroas are preparing for a joint party, a tradition they have upheld every four years.
"I don't care if we have dinner at a fancy restaurant or fish and chips on the beach but we will definitely be getting together to celebrate," Claudia said.
"Having our birthdays on the same day every leap year makes it so much more memorable."
According to an ancient Irish legend, a leap year is the only time a woman can propose marriage to her man.
In medieval Britain, a man was expected to pay a fine if he refused a marriage proposal from a woman on leap day.
And in some upper-class European societies, the custom of denial involved buying 12 pairs of gloves for the woman you were rejecting to hide her shame at not having a ring to wear.
In Greece however, getting married in a leap year is said to be unlucky therefore couples avoid getting hitched in these years.
In Scotland, it was even considered unlucky for someone to be born on leap day, just as Friday the 13th is considered an unlucky day by many.
But none of this bothered Nick Breen and his wife Amanda, who married in the back garden of their house on Auckland's North Shore on February 29, 2008.
They now have three children aged five and under, and like to do something special for their wedding anniversary every four years.
"We agreed we would go on an overseas holiday every time it comes around," Nick said. "We went to Rarotonga last time but we have exceeded our budget recently so we will probably have a quiet weekend away from the kids, somewhere like Rotorua or Taupo.
"We chose to get married on leap day because it is out of the ordinary. It was also a day I'd never forget."
West Auckland school student Ireina Paurini can't decide if she will be 12 or 3 on February 29.
Ireina, who attends St Dominic's College in Henderson, was born four days late in 2004. "She loves having her a birthday in a leap year because she gets to choose a nice holiday," mum Herena said. "The last time she chose the Gold Coast and she wants to go back there again and visit the theme parks.
"She will also be having some friends for a sleepover party next weekend and we will have a big family dinner the night before her birthday, so it will be a very busy and exciting time for her."
The family usually celebrates Ireina's birthday on February 28, the legal day those born on February 29 can observe their special day any other year.
There were 162 babies born in New Zealand on February 29, 2012, compared to 190 born on the same date four years previously.
People born on February 29 can also join The Honor Society of Leap Year Day Babies. More than 10,000 people worldwide have joined since the website was launched in 1997.
The twin cities of Anthony, Texas, and Anthony, New Mexico, are the self-proclaimed leap year capitals of the world. They hold a four-day leap year festival each leap year that includes a birthday party for all leap year babies.
Well-known Kiwis with leap day birthdays include Wellington composer Gareth Farr (1968) and former Warrior player Clinton Toopi, (1980).