Graph Showing The Most Common Birthdays Suggests That There’s A “Mating Season” Among Humans
Some say that “statistics mean nothing to the individual”. Sure, one could argue that statistics may not necessarily apply to specific people, but they still, nevertheless, explain our reality—the likelihood and possibility of certain circumstances and situations to happen given the number of cases over an average arbitrary measure.
Data Is Beautiful (r/dataisbeautiful), a significantly large subreddit (a subsection) of the forum-like social media Reddit, is dedicated to celebrating the various bits and pieces of information in the form of graphs and charts. One of the more recent posts to find itself here is an interesting graph showing the most and least common birthdays in the United States.
Ever noticed how there are more birthdays happening in the summer than in any other season?
Image credits: Bo McCready / SSA
The graph is divided up into individual days and months of the year, covering a span of 14 years between 2000 and 2014. Each day is color-coded using varying shades of blue, orange or gray. Blue means that a particular day has more births than usual, while the orange means it has less. Gray indicates that it’s relative to the average.
The numbers provided in each block indicate the margin by which the birth rate exceeds or falls short of the average, which is equal to 1. Anything under a 1 means that it’s not a popular birthday, while anything over that number means it’s common.
A Redditor recently compiled a beautiful graph showcasing the most and least common birthdays
Image credits: Bo McCready / SSA
According to this data, which is based on information made public by the Social Security Administration of the United States, “birthday season” starts sometime in June and ends in October. For the years 2000–2014, the most common birthdays were in September, namely the 12th and the 19th.
Fun fact, for the longest time, September 9th used to be the most popular birthday, but the 12th and the 19th were always hot on its heels. It is speculated that September is the most popular month for birthdays due to the fact that holiday season is 40 weeks prior to this, and, statistically speaking, more couples have sex during vacation time.
Turns out, summer is birthday season with September being the most popular month in that regard
Image credits: cobaltfish
This is paired up with a theory proposed by researchers at the University of Texas School of Medicine back in 2001 stating that there is reason to believe that winter is a more suitable time for reproduction due to the changes in daylight length, the variation in quality of the reproductive functions, and whatnot.
The least popular day is, however, Christmas (December 25th), followed by New Year’s (January 1st), Christmas Eve (December 24th), and surprisingly the US’ Day of Independence (July 4th).
The least common days are Christmas, Christmas Eve, New Year’s, and, surprisingly, 4th of July
Image credits: Bo McCready / SSA
Now, it’s quite sensible to say that you don’t really choose when to give birth—the body and the baby sort of decide the specifics, so it’s interesting to see these particular days, even within “the season”, to be the least common. It is also interesting to see how the 13th of each month is noticeably less popular than the adjacent days.
Another graph, also found on Reddit, covers a different time span, namely the ten years between 1994 and 2003, but shows pretty much the same results: birthing season is mid to end summer and September is still king.
It also points out that the 13th day of each month is often noticeably less common compared to adjacent days
Image credits: Bo McCready / SSA
It also gives other fun tidbits of information, like the most popular significant dates as birthdays being Valentine’s Day (February 14th), Friday 13th, and April 20th, a significant date in cannabis culture. The most popular day of the week is Tuesday, followed by Thursday, Wednesday, and Friday with the least popular being Sunday.
In much of the world, September stays the most popular month for birthdays, though the birthday season is slightly pushed towards winter season in countries within the tropical zone, and towards spring in the south temperate zone.
So, what are your thoughts on this? Were you born during the time when it’s cool to be born, or are you happy that your birthday is more personal as less people were born on it? Let us know in the comments section below!
Here’s how people reacted to these findings
It just means people have a little more sex around the holidays, and when it's cold. Makes sense.
My husband and two of his siblings are all born in November. Seems like a Valentine's day tradition for their parents. :-D Other sybling was born in August but, researching the family tree (birth date versus parents' recorded wedding date) I have my suspicions planning didn't come into it for the eldest. ;-)
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I was curious about Feb 29 too, so I found this in the linked source: "I used average births per day to adjust for the number of times each day occurs. EDIT: a lot of people have commented that this is confusing. I agree! I should have excluded February 29 or added a note explaining how I handled it."
In addition to the mentioned fact that fewer people schedule C-sections on holidays & "bad" days, sometimes it can be a conscious plan with other types of births as well. e.g. trying to induce the birth sooner to avoid the child having to share their birthday with Christmas, or trying to wait. Not always successful of course but I can see people trying. Maybe some hospitals will even let you fudge the numbers if you're close enough to midnight? Would definitely explain why Sept 12 is so popular if the 11th is least popular.
I don't know how it is in US, but in my country it is quite common that if someone is born close to midnight, then doctor may alter their date of birth. Especially when it comes to Dec 31/Jan 1, because this one day determines whether the child will go to school one year later or sooner. I believe that's also why all 13th days are less popular since 13 is regarded as unlucky number...
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The mother, even though it's likely subconscious, has the biggest say in all of this. Not on the day of conception, but on the day of birth.
It's simple, how many women are teachers? How many of them have summers off so having a baby won't affect their work schedule as much. My wife worked for a school district. Our daughter was born in early May. She was constantly told she should have planned better.
Mating season among humans. But the chart is for the United States only. I think this changes for countries that do not have seasons... We do not have winter or summer the same way as a countries with seasons do. That must affect I think.. Mmmm
A friend of mine was born exactly 9 months after her dad's birthday. Apparently her conception was his birthday present.
You have no idea how many people I met who were born between 19-23th of September (I myself was born on 21st of September). First time I noticed that when I was at school. I had other 4 classmates who were born during this period. 2 of them had their birthdays on 22nd of September. Now it would seem as a coincidence until you take into account the fact that my hometown is more a village (about 5 thousand people population) and has 1 school. Later in life I met more and more people born during this period. Seems creepy. Perhaps autumn equinox is at work there? Or the fact that during spring/summer fresh food is more readily available and so woman's body can support fetus' growth better?
Lol...people like to have sex on Christmas and New Years. Nothing to do with fresh food or the equinox. Your parents got drunk on New Year's Eve, had sex, and boom: 9 months later you came along.
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High schedules c-section rates is the reason for fewer birthdays on holidays.
What does "being an Australian" have to do with the fact that lots of babies are born around Christmas...?
I've been born at 28th of September and it was pretty quick clear to me why. In addition to holiday season we had regular power shortages at that time in Poland
Well, Christmas IS the most wonderful time of the year and the festive season makes the people a little more... loving.
You’re not taking into account c-sections and induced labor. Much revolves around the doctors tee-time.
This means nothing, people do not get pregnant on 11 th September so it is really co incidence except winter, nothing else much to do on some days in winter.
One of my kids was a Christmas/New Year conceived baby, that's about when we had our honeymoon, lol. Double whammy. I also have one of the less common birthdays, in a long life I've only met about 5 people with the same birthdday, one of them being my mother-in-law!
People plan for babies to be born in September so that they'll be the oldest in their school year group.
How does that make sense? My daughter is Jan 21 always the oldest in her class
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I have one kid with a super common birthday in September, and another born on Christmas Eve!
I was born on a 13th, although I was three days late. What does that count as?
I was born 2 weeks early (common for a 3rd child) on November 7th which means I was conceived on Valentine's Day.
Both me and my sister were born on the13th of the same month, 8 years apart.
Funny, me and most of my friends have our birthdays between October and April! I would assume the opposite!
"According to this data, which is based on information made public by the Social Security Administration of the United States." You might consider reading the article before making a comment.
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It just means people have a little more sex around the holidays, and when it's cold. Makes sense.
My husband and two of his siblings are all born in November. Seems like a Valentine's day tradition for their parents. :-D Other sybling was born in August but, researching the family tree (birth date versus parents' recorded wedding date) I have my suspicions planning didn't come into it for the eldest. ;-)
Load More Replies... I was curious about Feb 29 too, so I found this in the linked source: "I used average births per day to adjust for the number of times each day occurs. EDIT: a lot of people have commented that this is confusing. I agree! I should have excluded February 29 or added a note explaining how I handled it."
In addition to the mentioned fact that fewer people schedule C-sections on holidays & "bad" days, sometimes it can be a conscious plan with other types of births as well. e.g. trying to induce the birth sooner to avoid the child having to share their birthday with Christmas, or trying to wait. Not always successful of course but I can see people trying. Maybe some hospitals will even let you fudge the numbers if you're close enough to midnight? Would definitely explain why Sept 12 is so popular if the 11th is least popular.
I don't know how it is in US, but in my country it is quite common that if someone is born close to midnight, then doctor may alter their date of birth. Especially when it comes to Dec 31/Jan 1, because this one day determines whether the child will go to school one year later or sooner. I believe that's also why all 13th days are less popular since 13 is regarded as unlucky number...
Load More Replies... The mother, even though it's likely subconscious, has the biggest say in all of this. Not on the day of conception, but on the day of birth.
It's simple, how many women are teachers? How many of them have summers off so having a baby won't affect their work schedule as much. My wife worked for a school district. Our daughter was born in early May. She was constantly told she should have planned better.
Mating season among humans. But the chart is for the United States only. I think this changes for countries that do not have seasons... We do not have winter or summer the same way as a countries with seasons do. That must affect I think.. Mmmm
A friend of mine was born exactly 9 months after her dad's birthday. Apparently her conception was his birthday present.
You have no idea how many people I met who were born between 19-23th of September (I myself was born on 21st of September). First time I noticed that when I was at school. I had other 4 classmates who were born during this period. 2 of them had their birthdays on 22nd of September. Now it would seem as a coincidence until you take into account the fact that my hometown is more a village (about 5 thousand people population) and has 1 school. Later in life I met more and more people born during this period. Seems creepy. Perhaps autumn equinox is at work there? Or the fact that during spring/summer fresh food is more readily available and so woman's body can support fetus' growth better?
Lol...people like to have sex on Christmas and New Years. Nothing to do with fresh food or the equinox. Your parents got drunk on New Year's Eve, had sex, and boom: 9 months later you came along.
Load More Replies... High schedules c-section rates is the reason for fewer birthdays on holidays.
What does "being an Australian" have to do with the fact that lots of babies are born around Christmas...?
I've been born at 28th of September and it was pretty quick clear to me why. In addition to holiday season we had regular power shortages at that time in Poland
Well, Christmas IS the most wonderful time of the year and the festive season makes the people a little more... loving.
You’re not taking into account c-sections and induced labor. Much revolves around the doctors tee-time.
This means nothing, people do not get pregnant on 11 th September so it is really co incidence except winter, nothing else much to do on some days in winter.
One of my kids was a Christmas/New Year conceived baby, that's about when we had our honeymoon, lol. Double whammy. I also have one of the less common birthdays, in a long life I've only met about 5 people with the same birthdday, one of them being my mother-in-law!
People plan for babies to be born in September so that they'll be the oldest in their school year group.
How does that make sense? My daughter is Jan 21 always the oldest in her class
Load More Replies... I have one kid with a super common birthday in September, and another born on Christmas Eve!
I was born on a 13th, although I was three days late. What does that count as?
I was born 2 weeks early (common for a 3rd child) on November 7th which means I was conceived on Valentine's Day.
Both me and my sister were born on the13th of the same month, 8 years apart.
Funny, me and most of my friends have our birthdays between October and April! I would assume the opposite!
"According to this data, which is based on information made public by the Social Security Administration of the United States." You might consider reading the article before making a comment.
Load More Replies...
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