Dec. 20 most common birthday?

[snopes]

Comment: The number of babies born is about the same for each of the 365
days in a year. However December 20 has the largest number of birthdays.

This I was told about 30 years ago, is it true?

[mizzie]

Well, I have a close friend who turns 29 today, if that helps any.

[Eddylizard]

Okay that would put the date of conception at around March 1st - so what happens at that time of year that makes people stay in and create their own fun?

[ganzfeld]

Originally Posted by Eddylizard

Okay that would put the date of conception at around March 1st - so what happens at that time of year that makes people stay in and create their own fun?

The least common birthday of the year - Feb 29th. But that means there should only be an increase every four years... which means there should be fewer kids born on Dec 20 in years without a leap day...

[Not_Done_Living]

I also just returned from a friends birthday today (yesterday now i guess), and my Sis in law was born today at 12:03 am -- which would almost qualify.
I also dated a girl 20 years ago who was born on the 20th.. so there might be something to this.

[snopes]

Originally Posted by ganzfeld

The least common birthday of the year - Feb 29th. But that means there should only be an increase every four years... which means there should be fewer kids born on Dec 20 in years without a leap day...

No, you see, Dec. 20 is the most common birthday because babies conceived on both Feb. 29 and Mar. 1 are born that day!

[Ana Ng]

A quick Google search indicates that a lot of people are under the impression that 10/5 is the most common birthday, and that babies born on this date are likely to be conceived on New Years Eve. However, given that pregnancies last however damn long they feel like it, I don't think that babies born on one particular date all have the same likely DOC.

[Beejtronic]

Well, I don't know anyone with Dec. 20th as a birthday, therefore we can safely call this rumour false. Now let's never speak of this again.

[Mosherette]

Originally Posted by Beejtronic

Well, I don't know anyone with Dec. 20th as a birthday, therefore we can safely call this rumour false. Now let's never speak of this again.

Same here. I concur.

[mags]

Considering how many women I've heard of scheduling their C-section or inducement (weeks in advance), I wouldn't doubt this as being possibly true now, but 30 years ago?

Generally, it seems like now obstretricians want to be able to schedule working hours and vacations just like anyone else, and women want to know what date is the latest they'll have to wait to give birth (and want to be certain to have the doctor they are familiar with). December 20th would seem like a good last day for scheduling any woman who was due to give birth sometime over the Christmas and New Year holidays.

[Latiam]

My sister was born on the 20th long before scheduled C sections. Counting back I get April. Nothing comes to mind.

On the other hand, I was born almost exactly 9 months after Valentine's Day.

[Spud Sabre]

My grandma and my friend are both born on the 20th. Though I don't see what makes that day popular, or if it even is.

[Cervus]

When I was in grade school it seemed like a disproportionate number of us had birthdays in October.

[Dropbear]

Originally Posted by Latiam

On the other hand, I was born almost exactly 9 months after Valentine's Day.

My father was an accountant - I was born 9 months after the end of the financial year.

Dropbear

[Richard W]

Here's one study by month rather than day, based on students at Meredith College (an all-female college; this seems to be somebody's undergraduate thesis). The writer is comparing the patterns at her college with previous data for the US as a whole:

http://mste.illinois.edu/courses/mat...sisPape05.html

The data isn't broken down by day but the peak months are August and September, which apparently fits with other data.

The typical United States pattern for births is a September peak and an April-May trough; April-May births correspond to July-August conceptions, some of the hottest months of the year in America.

(From the page before.)

While many low points occur throughout the year, one day stands out above the rest with seventeen birthdays; this incident occurs on day 243 or August thirty-first, right in the middle of our two peak months.

That doesn't have much significance, but it's not December 20th anyway. It seems unlikely that a single day in December would be the most common birthday if there's an overall peak in August or September.

[lynnejanet]

Originally Posted by Beejtronic

Well, I don't know anyone with Dec. 20th as a birthday, therefore we can safely call this rumour false. Now let's never speak of this again.

Maybe not IRL, but I was born on December 20th. So, the rumour is obviously true.

[Steve Eisenberg]

I would have thought that December 31 would be the most common in the US, because of the negative tax implications of recording the birth the next day.

[purpleiguana]

My stepfather's birthday is the 20th, however, of everyone else I know IRL, AFAIK, his is the only birthday that falls on that day.

[Seaboe Muffinchucker]

My brother's birthday is the 20th, and we know about four or five others. But he was in his 40s before we met his virtual siblings.

I, however, had a twin in high school and my birthday's in May.

Seaboe

[Spam & Cookies-mmm]

Originally Posted by Steve Eisenberg

I would have thought that December 31 would be the most common in the US, because of the negative tax implications of recording the birth the next day.

But if you're going to induce labor, you'd schedule it in advance. I don't think the OB surgeons would want to schedule an induction on New Year's Eve, which would require them then to do a follow up hospital visit on New Year's Day.