Wednesday, Feb. 29, is Leap Day, the extra day that's added to the calendar every four years.
People born on Feb. 29 are known as "leaplings" and technically their birthdays only come once every four years.
Birth certificates and most government agencies, such as Social Security, use Feb. 28 for those born on Leap Day. But leaplings occasionally encounter bureaucratic difficulties with their true birth dates. Some computerized dropdown menus don't include Feb. 29.
Micah Shaffer, from Texas, is celebrating his seventh birthday.
"It doesn't really bother me. I guess you know 28 years or 7, however you want to say it," he said.
Leap Year was introduced by Roman emperor Julius Caesar and dates back to 46 B.C. It is a corrective measure to keep our calendar matching the four seasons and the earth's alignment with the sun.
"Most civilizations were on a lunar calendar, based on the phases of the moon. And the year was about 355 days long.
"But everybody, even those in grade school, knows that's not the length of the year," explained Dr. Norman Markworth, professor of astronomy at Stephen F. Austin State University in Texas.
"So, what they would do would be to add days here and there, every now and again, to try to get the calendar to catch up with the seasons. And sometimes, they'd add whole months, and these can be known as the Years of Confusion," he added.
Experts say the chances of being born on Leap Day are one in 1,461.
"My birthday feels like a cosmic joke," said Jan Harrell of Ashland, Orel, who turns 64 this week. "But not a bad one, just a very, very funny one."