But of course, when we speak about coincidences there is a much wide domain of search.For example, we could look at similarities in names, employment history, appearance, etc.Your question got me thinking, and I realized my girlfriend and I also have a strange birthday coincidence. So, first of all, the odds of sharing some weird connection with any random person are probably quite high.
But P(same day) should be roughly independent of whether you were born in the same year.
The larger you cast the search, the more possible bases there are for finding coincidences.
In general, the more you look for them, the more you will see them.
We've argued before about the probabilities and I am still not satisfied.
My point was that the chances are tiny if you consider the probabilities of being in a relationship ( being successful at it for X amount of time).