(Submitted by friend of the blog, Ross Blocher of Oh No, Ross and Carrie!)

My extended family was enjoying its annual trip to Disneyland in late November of 2008. While we typically go to celebrate my mom’s birthday, this particular Saturday happened to fall on my niece Shirley’s third birthday. She was the delightful recipient of many gifts and happy birthday wishes. You could be forgiven for thinking that Shirley is something of an older-fashioned name; she was named after my grandmother.

We’d made dinner reservations at the Big Thunder Mountain BBQ. As we arrived there we heard a guitar-playing cowboy on the stage announce, “Come on up here, Shirley. Let’s all sing Happy Birthday to Shirley!”

Everyone in our party started looking at each other. “Who told him? How do they know it’s Shirley’s birthday?” As my brother-in-law walked Shirley toward the stage, we saw that another little girl was being escorted up in front of the crowd. Before my brother-in-law could say anything, another man yelled out from the crowd, “Our daughter is Shirley, too, and it’s HER birthday!”

Now we felt like we had to prove that OUR Shirley was really named Shirley and was also having her birthday, because the coincidence was simply too amazing! Here we had three girls, aged three, four, and five, each with a traditional name that is apparently all the rage, sharing the same birthday!

All three Shirleys were serenaded by the crowd. It took a long time for my family to stop laughing.

Below are the extended notes provided by Barbara Drescher for use in Skepticality Episode 184. Take a look and leave your comments below. Please note that in the original version Ross sent us, the month and year were not included. Ross updated the story with more details after Barbara’s analysis and our recording.

When we are in the midst of these experiences, they seem astonishing, but there are a great many factors to consider when calculating the odds of such a thing. Although I cannot estimate those odds without some basic information such as the year in which this occurred, I think the list of factors will make it clear that the odds are greater than they appear.

• How unusual was the name “Shirley” at the time? Although I concede that it sounds old fashioned, the popularity of baby names is an interesting animal with somewhat cyclical patterns. Sometimes a name is popular simply because it is widely assumed that it will be unpopular and people tend to seek uncommon names for their children. ‘Shirley’ is considered uncommon according to several databases that I consulted, including Babypedia, but it peaked at #2 in 1935. Naming children after great grandparents is a common practice; my own youngest’s middle name is Patrick, after my grandmother (Patricia).
• How many girls born in the last decade or two had great grandmothers born during the name’s heyday?
• How many people visited Disneyland that day?
• How many young visitors to Disneyland that day were celebrating a birthday?
• How many of the visitors were within earshot of the stage on which this occurred? Keep in mind that it was a popular park restaurant at dinnertime.

I imagine the park performers who do such things have many stories like this one. Still, it’s fun and memorable when it happens to you because, although the odds are not shockingly low, it is uncommon.