Why is September the Most Popular Birth Month?

Why is September the Most Popular Birth Month?

Posted by Andrea Elliott on Sep 16th 2019

Expecting a baby or a birthday of your own this month? You're not alone. Not even close! Fun factoid - Nine out of the ten most popular birthdays in America fall in September.

September 9th to be exact, is the most popular day to be born in America, with September 19th as the runner up.

But why?

Winter is the perfect time to get it on!

If our math serves us correctly, 9 months before September brings us back to, you guessed it: December! But are we surprised? Definitely not! Winter Holidays mean more joy (and anxiety!) more down time, festivities and reasons to celebrate. More couch snuggling and not much else to do when that first winter blizzard hits!

The least common days to be born are all holidays: 12/25, 1/1, 12/24, and 7/4 -- and it's no surprise there, as inductions and c-sections are very unlikely to be scheduled on a popular holiday when Doctors hope to have a nice quiet day at home.

Mother Nature calls the shots!

Some also theorize that we're biologically programmed to conceive in the colder months. Science tells us that many living things tend to reproduce during the time of year that boosts their species' reproductive success. Humans are no exception and tend to follow an evolutionary phenomenon called birth seasonality, which has been studied extensively since the 1800's. It is believed that climate drives seasonal changes in fertility, with the ultimate objective to give birth when plenty of resources are available for the new offspring. 

This could be why testosterone levels are highest for both men and women between late fall and early winter. According to a study published in the journal Obstetrics and Gynecology, the winter season has various biological benefits in terms of pregnancy — the shifts in daylight length causes a better environment for eggs in women and males typically produce higher-quality, faster and more motile sperm during this time of year compared to the summer time. 

There you have it! Two solid theories that may very well be linked to one another, as to why your facebook feed is suddenly filled with so many birthdays this month!