Christian Lawson-PerfectI've just realised that I don't think I've ever met a married couple who have the same birthday, or even heard of one. It shouldn't be that rare, should it?
So: do you have the same birthday as your partner?
Niek van Leeuwen@christianp chance 1 to 365
Marlike@niekvleeuwen @christianp not so, if you count the birthyear as well.
Rick de Wolf@niekvleeuwen @christianp It's not the birthday paradox situation, so it's just 1 in 365. You've got to get to know a lot of couples or get quite lucky before you find any with the same birthday.
Le Néandertal se sent las, las@watchie @niekvleeuwen @christianp Christian has more than 5000 followers. I think this makes at least 2500 (independent) people with a love partner. The probability that none of them share their birthday with their partner is 1/1000....
@christianp friends of mine have the exact same birthday.
Martin Kimber@christianp Hypothesis: couples form, but cannot take the strain of sharing a birthday. Such couples never make it to cohabitation.
Σ(i³) = (Σi)²
David Hoeffer@christianp it's not a birthday paradox configuration, it's 1/365 (I think, not a mathematician), so given how many couples one typically knows of which one also knows the birthday - zero sounds good to me
asta v 
@dhoe
yeah exactly, birthday paradox is between _any_ two people in a group, while this is about a group of pairs. 1/365.24 is about correct
@christianp
yeah exactly, birthday paradox is between _any_ two people in a group, while this is about a group of pairs. 1/365.24 is about correct
@christianp
mjdxp
Karin@christianp My grandfather and his second wife shared their birthday.
Chris D.@christianp Two friends of mine who were married for over ten years were born exactly one year apart (well, at least on the same day of the year, "exactly" is exaggerating, but sufficient for the parameters of the question) so there's your second-hand evidence.
Answering another question which isn't what you asked, but it's a logical follow-up question: my late husband was born four and a half years after me, so his birthday was my half-birthday and vice versa.
olligobber@christianp I know a married couple with the same birthday, but a few years apart. Unfortunately one of them passed away just a couple of years ago.
Jaap Zeldenrust (he/him)@christianp
My uncle married a woman who has the same date of birth (so not just birthday) as him, and they also had the same last name even before they were married.
They only met because of their identical names and dates of birth, and also bad data modeling.
They both had insurance policies with an insurance company that identified its clients based on last name and date of birth, so they each regularly got mail intended for the other person.
@jozeldenrust wow! That has to be the winner for most coincidences.
@christianp depends on your definition of coincidence. Them having the same name, date of birth and insurance provider are all coincidences, but there's direct causation between those coincidences and them being married.
0xDE@jozeldenrust @christianp Did the insurance company become less confused about their identities once they married?
@11011110
I'm not sure about the back-end stuff at the insurance company, but by that time they were living together, so any possible address mixups were a non-issue.
@christianp
I'm not sure about the back-end stuff at the insurance company, but by that time they were living together, so any possible address mixups were a non-issue.
@christianp
Yaksh Bariya@christianp according to probability, it shouldnt be that rare, about one in 365.25 (i know you can be more precise but lets keep it simple). But I guess we humans have much complex ways of making matches, since atleast I havent met such a couple (or even heard of). But my sample size is really small considering I hate going out of the house for anything
Arthur van der Harg@christianp But how many couples do you know where you know both partner’s birthdays? So it’s entirely possible that you do know such a couple, but are unaware of it.
@ArtHarg indeed, but I think that they'd be more likely to mention if their birthdays were the same.
Heinh2@christianp No, we don't
Jacob Scharmberg@christianp my aunt has the same birthday as her husband
David Baakman@christianp My sister has the same birthday (day/month + year) as her partner.
(And I have the same birthday (day + month) as my mom.)
(And I have the same birthday (day + month) as my mom.)
Jé@christianp no but I know one 😀
Timon 🏳️🌈 🐻@christianp @ionica
My grandparents were both born on the same day in 1901, in the same town (Amersfoort, the Netherlands).
My grandparents were both born on the same day in 1901, in the same town (Amersfoort, the Netherlands).
@christianp my parents were born on the same date, one year apart. Their parents were married on the same date also one year apart and they were both the fifth child of their parents.
Evert-J█ ██⭕██@christianp
Don't know about that, but at my previous job we we're with 7 in a room and 4 of our partners shared the same birthday (10th of December)
Don't know about that, but at my previous job we we're with 7 in a room and 4 of our partners shared the same birthday (10th of December)