MARIETTA — Today is Feb. 29, a date which only occurs every four years. That makes today’s birthdays extra special for people like Den McGrew and Steven Phelps, two Kennesaw boys who are both turning 8, even though it’s only the second time their actual birthdays have come around.

Leap years, which have 366 days, are needed to keep our calendar in alignment with the Earth’s revolutions around the sun. According to timeanddate.com, “it takes the Earth approximately 365.242199 days — or 365 days, 5 hours, 48 minutes, and 46 seconds (a tropical year) — to circle once around the Sun. However, the Gregorian calendar has only 365 days in a year, so if we didn’t add a day on February 29 nearly every 4 years, we would lose almost six hours off our calendar every year. After only 100 years, our calendar would be off by approximately 24 days!”

Steven Phelps, a second-grader at Kennesaw Charter School, said he likes his special birthday.

“It feels like I get two birthdays,” he said. His mom, Diana, said that when she was pregnant in 2004 and realized a leap day birth was possible, she was initially unhappy. Her due date was March 3, but Steven apparently had other ideas. He was born naturally three days early at a hospital in Clayton County, where the family lived then.

“He has a party every year, but every four years, I go all out and try to make it as special as we can,” she said. “He sometimes gets upset when his friends have an actual birthday every year.”

Her son, she said, is a typical 8-year-old boy.

“He’s wild and crazy — definitely all boy,” she said with a laugh. She thinks his special birthday is neat.

“I’m surprised at how many people don’t understand leap year,” she said. “How do adults not know about leap day?”

Den McGrew, who was born on Feb. 29, 2004, at WellStar Kennestone Hospital, likes to confuse people when they ask how old he is. Until today, his answer was usually 1, “because that’s really how old I am!”

“My stuffed animals are older than me, and it sounds funny when I say that,” Den said with a laugh.

He says its cool being a “leapster” — though he doesn’t get extra presents or cake on his leap day birthday.

“I wish I did, but no,” he said. “But every time that I have a leap day birthday, we have a really big party.”

Den is the son of Dennis and Mandy McGrew, who met as teenagers at Sprayberry High School. The family also includes Annika, who is 5.

Mandy McGrew said that when she was pregnant in 2004 and her Feb. 23 due date came and went, she knew what would be her day.

“I just thought, with our luck, he’d be born on leap day,” she said. And there’s only been a little craziness to accompany the deal, she said.

“He keeps getting dropped from the Toys R Us birthday club because they don’t think his birthday exists,” she said.

But even Den, at only 8 years old, understands the concept.

“My mom said that if we didn’t have an extra day every four years, the days would get all mixed up,” he said.

Obstetrician Vidya Soundararajan has two patients who specifically wanted to deliver their babies today at WellStar Cobb Hospital, though one already went into labor. The other is to have a C-section today. Sometimes it’s the other way around, and patients try to avoid the day. Regardless of the date, WellStar policy prevents elective deliveries before 39 weeks of pregnancy.

“People are very aware of dates, but it’s just another typical day at work for us,” Soundararajan said.