By DAVE STEPHENS - Follow me @MrDaveStephens South Bend Tribune Staff Writer

5:10 p.m. EST, February 16, 2012
SOUTH BEND —
After they had left the hospital, after the TV camera crews had come and gone, the Marques family returned to their apartment Thursday and tried to comprehend it all.

Baby Grace, perhaps, had it the easiest.

Only three days old, with a newborn's wrinkly skin and a set of cheeks that would do a chipmunk proud, it was clear she understands her place as the center of her parents' universe.

It will be some time yet before she realizes that her birthday ... Feb. 13 ... is also the day her mom Kelly and her dad Dan were born.

But for her parents, the question lingered.

What was the odds?

The answer depends where you begin.

First, they meet.

Purely statistically, and assuming that births occur evenly throughout the year (they don't, but more on that later) the odds of any two people sharing the same birthday is 1 in 365, or about 0.27 percent.

Simply put, that means when Dan and Kelly found out on their very first date that they shared a birthday -- "I made him show me his driver's license because I didn't believe him," Kelly said -- they already were beating some long odds.

When they decided to get married -- Dan said he pushed for a Feb. 13 wedding date, using the guy's logic that if everything happened on the same day, it would be easier to remember -- those odds became part of something bigger, an agreement to spend their birthdays together for the rest of their lives.

Then came last year when Dan and Kelly -- he a 29-year-old second-year MBA student at Notre Dame, she a 30-year-old dietitian -- learned they would be having a baby.

The due date, doctors determined, was Feb. 4.

Again, they were bucking the odds.

Although births occur throughout the year, in the United States births do have a slight seasonal adjustment, with more births occurring in August and September, followed by the other summer months, according to Census data.

February (in part because it's the shortest month) has the fewest births, followed by November.
Regardless of the statistics, however, Grace was slated to arrive the first week of February.

"We kind of joked about her being born on our birthday," said Dan, who added that the jokes weren't completely appreciated by his wife.

"I didn't think I'd go nine days past my due date," Kelly said.