In Japan the question "What's your blood type?" is as common as "What's your birth sign?" in America, as the result of a study connecting blood type with personality.

Blood types are taken very seriously there; when people look at a family where the members seem to excel in show business, sports or even criminal activity, it's often said "it's in their blood."

Though not as widespread in America, researchers here have also found startling similarities among each blood type. Why?
Because your blood type often reflects your internal chemistry, including the brain chemicals that make up your personality.

Here's a brief look at the personality traits associated with the four main blood types:

blood types

Type O-You want to be a leader (or have leadership qualities). When you see something you want, you keep striving until you achieve your goal. You're a trend-setter, loyal, passionate and self-confident. Your weaknesses are vanity, jealousy and a tendency to be too competitive.
Did you know that you're the original blood type? Once, all Cro-Magnon people who lived around 40,000 B.C. were type O.
O's are secretly romantic at heart!
Famous O's include Jackie Kennedy Onassis and Elizabeth Hurley.

Type A-You like harmony, peace and organization. You work well with others and are sensitive, patient and affectionate. Your weaknesses are stubborness and an inability to relax.
As the Cro-Magnons evolved, they developed more society-building skills. That's when A blood types began appearing.
You're a traditionalist in love.
Among some famous A's are Christina Applegate and George Bush Sr.

Type B-You're a rugged individualist who's straightforward and like to do things your own way. Creative and flexible, you adapt easily to any situation.
But your insistence on being independent can sometimes be too extreme and become a weakness.
Type B can be traced back to around 10,000 B.C. This blood type came about once men and women began migrating.
A high proportion of self-made people are Type B.
You enjoy being around people, and others love to be around you. Among friends, you'd rather listen to what everyone has to say before offering your opinion.
Some famous type B's are Paul McCartney and John F. Kennedy Jr.

Type AB-Your're cool and controlled, generally well-liked and always put people at ease. You're a natural entertainer who's tactful and fair. But you don't need to be with others to be happy.
Your weak points are sometimes being standoffish, blunt and having trouble making decisions.
You're truly unique; your blood type occurs in fewer than 5% of the population! AB is the most recently developed of the blood groups-going back to about 1,000 years ago. AB is also the most psychologically complex!
You can be both technical and creative.
In close relationships, you can be all business, then gushing and sentimental-often switching between the two.
You can sometimes be too strict with yourself and those close to you; it often seems as if you have a personality for those "outside" and another for people "inside".
Famous ABs include Thomas Edison, Marilyn Monroe and Jackie Chan.