Originally posted by Kaji
It's not for medical reasons that they want to know. It's because, as stated in the first post, it is said to determine one's personality. From what I recall, A's are supposed to be the kind that are overly stressed out from being perfectionistic and driven, B's are supposed to be intellectual (I think, it's been a while), and O's can probably best be described by citing Eikichi Onizuka from GTO as an example.
That looks pretty close, actually. Here's a link that explains all. I don't know what type I am in reality (should be on a birth certificate?), but if there is anything to this at all it should come out B.....


http://allsands.com/Health/bloodpersonali_bhy_gn.htm