Why Is September the Most Popular Birthday Month in the U.S.? People Have Theories

Who's celebrating their birthday here? All six of them.
Who's celebrating their birthday here? All six of them.
FlamingoImages/iStock via Getty Images

Maybe you’ve come across one or two people over the years who share your birthday. If you were born in September, that number might be a little higher.

In 2016, data journalist Matt Stiles analyzed the number of U.S. births by day from 1994 through 2014 and found that September is the busiest month to bring home a bundle of joy. September 9 is the most popular birthday overall, with 12,301 births on average, and eight other September dates surpassed an average of 12,000 births, too.

So why exactly is September such a high-traffic time to experience the miracle of childbirth? Flipping through the calendar could give us a hint. Pregnancies are supposed to last 38 weeks from conception, which means that babies born on September 9 would’ve been conceived on December 17. The conception date for the second most popular birthday, September 19, should technically be December 27. Of course, babies don’t always decide to make their appearance precisely at the 38-week mark, but the gist is that September babies were conceived in December. As Motherly points out, people tend to work less during the holidays, leaving more time to bounce from party to party, drink a few extra cocktails, and further the family line. It’s also a romantic season in general; according to a 2018 survey by Brides, December is the most popular month to get engaged.

Scientists have proposed their own hypotheses to explain the high conception rates in December, but they’re still mostly speculation. One theory suggests that sperm are less potent during the summer; according to another, the mother's eggs or uterine lining is less receptive to sperm during those months. Others think shorter daylight hours during the winter could affect our hormone functions.

It’s also possible that some people simply think September is an opportune time to have kids. As Experian explains, there aren’t any huge holidays to celebrate, so you can plan an induced or elective birth without worrying about short-staffed hospitals.

Whatever the reason, if you’re tired of having to schedule your birthday shindig around all the other ones in September, you can always throw yourself a half-birthday party, instead—far fewer people were born in March.

[h/t Motherly]

Thursday’s Best Amazon Deals Include Guitar Kits, Memory-Foam Pillows, and Smartwatches

Amazon
Amazon
As a recurring feature, our team combs the web and shares some amazing Amazon deals we’ve turned up. Here’s what caught our eye today, December 3. Mental Floss has affiliate relationships with certain retailers, including Amazon, and may receive a small percentage of any sale. But we only get commission on items you buy and don’t return, so we’re only happy if you’re happy. Good luck deal hunting!

The Meanings Behind 25 Common Acronyms and Initialisms

Remember POGs?
Remember POGs?
Rick Beauregard, Shutterstock

Before POGs became collectible items printed with our favorite ’90s pop culture characters, they were just simple discs found inside bottle caps. In fact, that’s how they got their name—POG is an acronym for Passion Fruit, Orange, Guava, the name of a Maui-based beverage whose lids gave rise to the game.

On this episode of The List Show, Mental Floss host Justin Dodd is sharing the origin stories behind 25 popular acronyms and initialisms, many of which you may not have realized actually stood for anything at all. Geico, for example, isn’t a word that insurance providers made up to match their spokes-gecko; it’s an acronym for Government Employees Insurance Co., made up to match the company’s original target demographic (government employees). And since LED stands for light-emitting diode, the phrase LED light is rather redundant.

Press play below to uncover the secrets behind other popular abbreviations, from Alien Life Form (ALF) to Yet Another Hierarchical Officious Oracle (Yahoo!).

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