Then I heard another interesting thing from a reliable source - well as far as unsolicited emails go - that if you take a class of 32 kids, the chances that at least any 2 of them share a birthdate is as high as 50% !

It's actually a 50% probability when there is a sample of 23 random people, at 30 the probability increases to 70%.

I do not know anyone personally who shares my birthday. Although, Valentino Rossi was born on the same day, but that's nothing even related to this discussion because I don't actually know him. (I thought that was true based on my brother's encyclopaedic knowledge of bikes, but it turns-out that it is not even close).

But the main difference here between the probability of any random two people sharing a birthday (any birthday) and people who share your particular birthday is radically different.

The chances that I would share a birthday with someone in particular (say you, Mintaka, for example) is 1 in 365, the chance that we would both share it with a particular third person (say bluegrayV) is 1 in 133 225. A particular fourth person would be 1 in 48 627 125. This is only because I don't know your birthdays. If I do know your birthdays, and they are the same then the probability is 1 in 1. Odd, huh?

ETA: There's an experiment on this at Richard Wiseman's blog,

here.

James