The discovery that solved transfusion's puzzle
From the 17th century on, transfusion attempts alternated between success and fatal failure. In 1901 Karl Landsteiner in Vienna mixed his colleagues' blood and found that some combinations made red cells clump, distinguishing groups A, B and C (now O). The next year Alfred von Decastello and Adriano Sturli found AB. In 1910 Emil von Dungern and Ludwik Hirszfeld showed that blood groups are inherited by Mendel's laws, and in 1919 Ludwik and Hanna Hirszfeld, testing soldiers of many nationalities on the Macedonian front in the First World War, reported that group frequencies differ among populations. Landsteiner received the 1930 Nobel Prize.
ABO, Rh and inheritance
Type A red cells carry the A antigen, type B the B antigen, AB both and O neither. Plasma holds antibodies against the antigens you lack, so mismatched blood triggers an immune attack that destroys red cells. In 1959 Winifred Watkins and Walter Morgan showed that the antigens are differences in sugar chains on the cell surface, and in 1990 Fumiichiro Yamamoto and colleagues found that the ABO gene encodes a sugar-attaching enzyme, with A, B and O arising from small base differences. Work by Philip Levine and Rufus Stetson (1939) and Landsteiner and Alexander Wiener (1940) revealed the Rh factor. An Rh-negative mother carrying an Rh-positive baby can make antibodies that attack a later fetus — haemolytic disease of the newborn — now largely prevented by anti-D immunoglobulin injections developed in the 1960s.
Transfusion rules and the personality myth
Type O Rh-negative red cells can be given to anyone in an emergency, hence "universal donor"; AB is the universal donor for plasma. Safe transfusion still requires cross-matching beyond ABO and Rh. Rh-negative blood is rare in East Asia, under 1% of people. The link between blood type and personality was first proposed in 1927 by Takeji Furukawa in Japan and became a craze through popular books in the 1970s, but a 2014 analysis of surveys of more than 10,000 people in Japan and the US found no meaningful relationship. Some studies report slightly higher risks of blood clots and certain diseases in non-O types, but not enough to decide an individual's health, and blood-type diets lack good evidence. Consult a clinician about blood-type issues in transfusion or pregnancy.
This article is general health information and is not a substitute for diagnosis or treatment. If symptoms persist, see a doctor.
FAQ
- Can two type A parents have a type O child?
- Yes. If both parents are genotype AO, each can pass on O, giving a one-in-four chance of an OO — type O — child.
- Can blood type reveal personality?
- Large surveys have found no meaningful link between blood type and personality. Enjoy it as fun, but avoid using it to judge people.
Sources reviewed: 2026-10-26
References
- Landsteiner, K. (1901). Über Agglutinationserscheinungen normalen menschlichen Blutes. Wiener klinische Wochenschrift, 14, 1132–1134.
- von Decastello, A., & Sturli, A. (1902). Über die Isoagglutinine im Serum gesunder und kranker Menschen. Münchener medizinische Wochenschrift, 49, 1090–1095.
- von Dungern, E., & Hirszfeld, L. (1910). Über Vererbung gruppenspezifischer Strukturen des Blutes. Zeitschrift für Immunitätsforschung, 6, 284–292.
- Hirszfeld, L., & Hirszfeld, H. (1919). Serological differences between the blood of different races. The Lancet, 194(5016), 675–679.
- Furukawa, T. (1930). On the relation between blood groups and temperament. Journal of Social Psychology, 1(4), 494–509.
- Levine, P., & Stetson, R. E. (1939). An unusual case of intra-group agglutination. JAMA, 113(2), 126–127.
- Landsteiner, K., & Wiener, A. S. (1940). An agglutinable factor in human blood recognized by immune sera for rhesus blood. Proceedings of the Society for Experimental Biology and Medicine, 43(1), 223.
- Watkins, W. M., & Morgan, W. T. J. (1959). Possible genetic pathways for the biosynthesis of blood group mucopolysaccharides. Vox Sanguinis, 4(2), 97–119.
- Yamamoto, F., Clausen, H., White, T., Marken, J., & Hakomori, S. (1990). Molecular genetic basis of the histo-blood group ABO system. Nature, 345(6272), 229–233.
- Nawata, K. (2014). No relationship between blood type and personality: Evidence from large-scale surveys in Japan and the US. Japanese Journal of Psychology, 85(2), 148–156.