My MIL believes that blood type indicates personality, it's the equivalent of zodiac signs in the West.
If you read the descriptions, they sound a lot like the instinctual variants.
A = so/sp, sp/so, sp/sx
B = sp/sx, sx/sp, sp/so
AB = same as A
O = sx/so, sx/sp, so/sx
Obviously not scientific by any means, but hey, I'm a blood type B- and it works for me.