Scientific research suggests that blood groups A, B, AB, and O may influence vulnerability to certain diseases and health conditions, though no single type is superior. Type A is linked to higher cholesterol and certain cancers but may protect against norovirus. Type B shows some disease resistance but is associated with higher risks of heart disease and diabetes. Type AB, the rarest, is linked to inflammation and clotting risks. Type O offers the lowest risk of heart attack and stroke but is more vulnerable to ulcers and bleeding.