According to a Harvard study, September 16 is the most popular for birthdays. How popular is your birth date?

Did you notice a lot of birthday notifications on Facebook yesterday? Chances are, you know quite a few people whose birthdays fall in September. In fact, it was my birthday last Tuesday. I share it (reluctantly) with two other friends, my Pilates instructor and a neighbour.

As it turns out, September 16 is the most common birthday of the year, while my birth date—September 9—comes in second. September actually has 10 of the most common birthdays of the year overall—which means that Christmas break is a busy time of year for many couples.

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Check out this infographic that was developed to show the most common birth dates over the last two decades. It comes from stats compiled by a Harvard public policy professor that was published in the New York Times in raw data form.

December 25 is shown as the least common birth date—and this may speak to doctors’ holidays as much as anything else. However, February 29, which appears once every four years, is technically the least common birth date. Other holidays, like American Thanksgiving and the Fourth of July also have low birth rates.

Once you know the most common birthdays, the conversation naturally turns to the most popular times for conception. The cold weather and December celebrations is credited to the cluster of birthdays in September. July and August are also popular months, which leads me to believe that as soon as the weather starts to chill, couples start to warm up to one another.

Both of my sons were due on March 27, which has a direct line to the July long weekend. And, if you count backwards from my daughter’s Christmas Eve birthday, you end up at my husband’s birthday. (Is this TMI?) I’m not sure why special dates were luckier in our calendar, but I’m happy that they were.

When is your birthday? How about your kids? Can you find a link between their birthday and a special occasion in your life?

Emma Waverman is a writer, blogger and mom to three kids. She has many opinions, some of them are fit to print. Read more of her articles here and follow her on Twitter @emmawaverman.