Why September Is The Most Popular Month For Birthdays

baby happy in fallen fall leaves

In case you haven't noticed, there are a lot of birthdays in September. While your news feed might be littered with back to school pictures, there's bound to be the odd birthday cake thrown in there, too. If you thought that it was a phenomenon restricted to your circle, think again. September is the most popular birth month in America, and there are three very interesting reasons why you may see more than usual, according to Reader's Digest.

Data journalist Matt Stiles looked at 20 years of real birth data from the U.S. National Center for Health and Statistics. He found that a single week and a half between September 9th and September 20th contains nine of the top ten birthdays in the country.

Out of all the days, the top three were the 9th, 19th, and 12th in that order. Stiles' findings didn't just stop at what dates were common, but fell to the other end of the spectrum, too. Christmas Day, New Year's Day, Christmas Eve, and July 4th are the unlikeliest birthdays, respectively. Surprisingly, births on these days are even less heard of than birthdays on February 29th. Why? Well, it all comes down to this intriguing theory.

baby with Down syndrome is resting in autumn forest
Credit: iStock

People like to snuggle in winter. It doesn't take a genius to figure out that babies born in September were conceived in December. A lot of people take some precious vacation time at that time of year, while in general, it's a very family-orientated, relationship friendly month. Plus, it's cold, and our bodies could be designed to copulate more in winter, according to a study by the University of Texas School of Medicine. The research suggests that sperm quality often deteriorates in summer, while in general, couples spend more "quality time" together in the bedroom around the Christmas holidays.

Stiles is quick to point out while it may look like September leads the way, the difference between the popular birthdays and less popular is often just a few thousand. In a group of 20 people, it's likely that at least two will have the same birthday. So, seeing those birthdays on your timeline could be partly to do with the number of friends you have on Facebook, as well as the effects of mulled wine on the masses!

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