Katie Gwyn turns 16 today — on her fourth actual birthday.

The Everett teen’s mom, Julie Frauenholtz, has figured out that her daughter, born Feb. 29, 1996, will miss lots of milestones. Her actual birthdate won’t land on the years she turns 18, 21, 30, 50 or 75.

“She won’t get another big birthday until she is 40,” Frauenholtz said. That’s not until 2036.

Way down the road, she can look forward to 60th, 80th and 100th birthdays.

Such is the timetable for people born on leap day, Feb. 29.

With the Gregorian calendar, that’s the day added every fourth year to make up for time lost when a year is computed as 365 days. It really takes about 365.242 days for the earth to complete its orbit around the sun.

For Katie, there’s more math this year, but it has nothing to do with celestial orbits. It’s a fun way the Everett High School sophomore has been counting the days until her 16th birthday.

Her mother planned a present-a-day surprise. Starting Valentine’s Day, the teen has opened 16 gifts, one per day. Among her birthday gifts are golf shoes, a swimsuit for a June trip to a cheerleading event in Hawaii, and the movie “Leap Year.”

The film’s plot borrows from an ancient Irish legend in which romantic tables are turned, and women are the ones to propose marriage on leap day. Some superstitions link leap years to bad luck or to nature being out of whack.

That’s not how Damon Dotson sees it. He and his wife Anisa, who live near Mill Creek, are expecting their second daughter. Anisa Dotson is scheduled to deliver the baby by Caesarean section today at Providence Regional Medical Center Everett’s Pavilion for Women and Children.

“The doctor said our due date was March 5, but they had to do a C-section about a week before. That’s the 29th,” Damon Dotson said Monday. “I thought it was great. I can’t think of anybody I knew growing up who had that birthday. It’s kind of a rare opportunity.”

Julie Moore of Snohomish had a twist to her birthday. Moore was born Feb. 29, 1960, and is turning 52 today. Her late mother, Judy Ingram, was also a leap baby, born Feb. 29, 1940.

Moore can hardly remember her first real birthday, when she turned 4, but has pictures from a Seattle newspaper. In 1964, she and her mother were treated to a free birthday dinner at the top of Seattle’s Space Needle.

“It connected me with my mom,” said Moore, who grew up in Mountlake Terrace. Through the years, Moore said they disagreed on when to celebrate when it was leap year. “Mom preferred Feb. 28. She said she was born in February, not March,” said Moore, who favors a March 1 celebration. “I wasn’t born the day before I was born.”

Marysville’s Edith Scott had her first child, Elsie Mae, on Feb. 29, 1944. Her daughter lives in Oregon and turns 68 today. Scott, 87, said a boy was born that same day at what was once Everett’s Providence Hospital.

Diana Rank, of Everett, has leap twins. Her sons Jakob and Dylan Rank are 12 today. The fraternal twins, sixth-graders at North Middle School, were born Feb. 29, 2000. Her delivery was also a planned C-section. Rank said the doctor gave her a choice of dates, but the hospital schedule was full for Feb. 27.

“It’s kind of cool. Leap year is something different,” said Rank, who also has 4-year-old twins, a boy and a girl.

When Jakob and Dylan were small, the concept of leap year was too complicated to understand. “I can explain it now. They think it’s cool,” said Rank, who hoped to give her boys a birthday cake decorated with a frog jumping over a frog.

In Lynnwood today, Danica Luyombya is celebrating her eighth birthday. Kylie Kingen, Danica’s mother, said her daughter will celebrate this weekend at Jump Planet, a party center in Bothell with inflatable play areas. “We’re doing the whole leap theme,” Kingen said.

Danica, she said, “was a very special baby.” Born with heart problems, she had bypass surgery at 11 months old at Children’s Hospital Medical Center. “She realizes it’s special,” Kingen said of Danica’s leap day birthday.

Dotson, whose wife is scheduled to give birth today, can’t wait to meet his leap day daughter, who’ll join 3-year-old sister Alexandra.

Deb Sibolski, manager of the Providence Family Maternity Center in Everett, said that unlike Christmas and New Year’s Day, when first babies get gifts, the hospital doesn’t do anything special for leap babies. “It’s one of those days parents don’t get too excited about,” Sibolski said.

Awaiting his baby’s arrival, Dotson learned that people have strong feelings about Feb. 29 birthdays.

“I love it and my wife would rather it be another date,” he said. “People seem to be polarized — more than Republicans and Democrats.”

Julie Muhlstein: 425-339-3460, muhlstein@heraldnet.com.

Leap facts and lore

Leap year: A year of 366 days in the Gregorian calendar, occurring every fourth year.

Leap day: Feb. 29, the extra day, makes up for time lost when the approximate 365-day-and-six-hour cycle is computed as 365 days.

Astronomical year: The time taken for the earth to orbit the sun is about 365.242 days.

Leap numbers: A leap year occurs on every year divisible by four; or, in the final year of a century, by 400. The difference between the approximate .25 day and the more accurate .242 day accumulates over centuries. That discrepancy is adjusted by adding a day only to century years exactly divisible by 400 (the years 1600 and 2000 are examples).

Leap babies: People born Feb. 29 are sometimes called leaplings.

Leap proposals: A centuries old tradition (a 1288 Scottish law is sometimes cited) holds that leap years allow women to propose to men, rather than the other way around. In an Irish legend, St. Bridget made a deal with St. Patrick to let women propose to men on leap day.

Leap superstitions: Some in ancient times believed leap years sent nature awry, and that crops, livestock and leap-day infants would not thrive.

Sources: Webster’s New World College Dictionary, Kidport Reference Library, About.com, Britannica.com