"Were I to guess, most of the people making the error don't know the difference between "Astrology" (not science) and "Astronomy" (science). Even the folks I know who are into signs and horoscopes wouldn't call it science. The funny thing, IMHO, is that as pseudo-science goes, it's actually not *total* BS. Well, the part where it has anything to do with constellations of stars is total BS, but as far as how it relates to personality it might not be. Malcolm Gladwell pointed out in Outliers that the birthdays of NHL players tend to be clustered around just after the cut off for the junior leagues. The reasoning is pretty straightforward. If you're born just after the cutoff date, you're almost a year older than someone born just before it. Bigger kids will be the best at almost any sport. They'll get the extra coaching to make them even better, encouraged to try out for higher levels, and eventually make the pro leagues. All because of their birthday. I can attest to it personally in..." - Eric P