Does this make any sense? There are many different blood factors that have been discovered, 29 actually. The only two that really matter are the ABO factor and the Rh factor because they are mostly what you have to know to match for a transfusion. To make sure of any other possible conflicts they also cross-match the recepient and the donor's blood because some of the other 27 can make a difference under rare circumstances. It is true that A is the only factor that has subtypes, mainly A1 and A2 but this is usually ignored because it doesn't affect a transfusion. 95% of A people are A1. So you would think that possible Beth was A2 but the main population of people that have A2 are brown-eyed Lapplanders. As for her being AO that is not rare. You inherit a blood type from each of your parents A and B are dominate and O is recessive. If you get an A from one and a B from one you are AB, if you get A from one and O from one you are AO, but you would have to do more testing of the blood than the Red Cross bothers with or know that one parent was type O and the other A or AO and you would then have to be AO if you were an A. In Rh factor + is dominant and - is recessive. You can be a negative if both parents are actually +-. They would test positive and you would have inherited the - from each one. I happen to be A- so I am interested. Since I don't know my parents' types I don't know if I am AA or AO, but since O, although recessive, is the major blood type in the US including American Indians (I don't know about people of African descent) it is very likely that in fact I am AO-. Now I am not that special and I have the company of about 6% of my country's population. So if they wanted to make Beth and Coraline's blood type special, why didn't they make it special. And why would Beth even know what her blood type is?