Fred Shekoufeh looks a lot older than 15, but then again his son, Eric, doesn't look four either.
Shekoufeh and son, who live in La Mesa, California, share a unique bond that goes beyond genetics: They were both born on February 29.
The calendrical quirk means that even though the older Shekoufeh will celebrate 60 years on Earth on Monday, it will only be his 15th official birthday.
Eric is celebrating his 5th official birthday the same day. Both father and son were born on February 29, an event that has a 1 in 2.1 million chance of happening, according to Time.com.
Fred Shekoufeh, a native of Iran, didn't realize his birthday was unusual until 1979 when he moved to the U.S. and immigration officials commented on it.
It wasn't clear at first.
"It's confusing," Shekoufeh told HuffPost.
Since then, he celebrates his birthday when he can, but admits it's hard to top 1996, when he turned "10" in a hospital delivery room.
"My ex-wife was in labor and said, 'This is your birthday present,'" Shekoufeh said. "When the doctor found that out, she said, "I will try to bring that baby out so it can share your birthday."
Eric Shekoufeh said sharing such an unusual birthday with his dad is "pretty incredible," but admits being born on February 29 has some challenges.
"I get lots of jokes about whether I should celebrate on Feb. 28 or March 1," Eric said, adding that he tries to stretch it out on both days.
"It's a weird day. People don't recognize it on social media, but when they find out, they never forget it."
Eric's favorite Feb. 29th birthday was in 2012, when he turned "four."
"Everyone and their mother made a joke about me turning four, and that four-year-olds shouldn't be able to drive cars. Well, evidently I could," he said. "I was glad to have an actual birthday on such on emphatic year: getting a license. No confusion at the DMV. I hope I can say the same when I'm going out for my 21st."
This year, Shekoufeh, a student at UCLA, plans to do more of his celebrating at Big Bear over the weekend.
"I don't plan to push it over to March 1st," he said.
However, he admits his focus is more on next year, when he will officially turn 21.
"Legally, I should be able to drink on the 28th, but I'm expecting a bouncer to look at my license and tell me it's a fake," he said.
Fred Shekoufeh admits his birthday plans this year are more focused around his son.
"I just sent him a couple of hundred dollars of whatever he wants from Costco, and a few hundred dollars so he can party hearty," he laughed.