We've argued before about the probabilities and I am still not satisfied. I will not give a URL as several of the copies on the internet may violate copyright; nevertheless it's easy to find @jerad: "..probability that the person sitting beside you on the bus..." but the odds are that I wouldn't be in a relationship with everybody that I meet on the bus, doesn't that account for anything?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). My boyfriend was arguing the same point you are but the relationship part is what's making me doubtful of the validity.This is based on the position of the stars and planets when they are born.If you believe this way, you likely know that you are most compatible with certain signs, based on the personality traits that that individual posesses.Based on all this, it would have to be judged on a case to case basis but really the only judgment that matters is yours.
After making these preposterous assertions, Math then goes on to rationalize its claims by recruiting its bastard offspring: numbers and formulas.I share the same birthdate as my boyfriend, same date but also same year, our births are seperated by merely 5 hours or so.I know that the chances of meeting someone who was born on the same date than me is fairly high and I know a few people with whom I share my birthday although for the little I've read about the birthday paradox, it doesn't take same year into account. Journal of the American Statistical Association 84: 853-861.But P(same day) should be roughly independent of whether you were born in the same year.So it will be $\approx$ P(Same year) $\times$ P(Same day).Try to step out of your comfort zone and open up if you want this relationship to work.