Characteristics of a positive blood type

Understanding Blood Type Personality | BetterHelp

In America, some people look up a potential partner's star sign to see their personality type and compatibility. If you are not too shy to admit it, you may have sought advice on this and relationships from the stars at one time or another. Some people do not rely on the astrological signs of personality information but rather on their biological markers. Continue reading to learn about this unique take on what makes us individuals and see how it may apply to you or someone you know. We will also provide resources for online therapy services if you're interested in diving deeper into self-discovery.

Learn More About The Four Blood Types And Their Associated Personality Traits

Click Here To Get Matched With A Licensed Therapist

In Japanese society, the dating set might ask someone what their blood type is to learn more about them. It may surprise you to learn there is a whole blood type personality theory that has become popularized in Japan.

All You Need To Know About Blood Type Personality

What Is Blood Type Personality?

The concept of blood type personalities might seem foreign to us, yet understanding blood typing is quite popular in certain countries. Some believe that personalitytraits are inherently connected to the type of blood you are born with. Although a potential link between blood type and personality is a fun idea, there's currently no scientific proof to back up blood personality type, meaning the overall theory of blood type personalities is to be viewed as more of a fun myth than a scientific fact.

Similar to how some Americans like to entertain the idea of astrology and horoscopes for fun, some people in Japan enjoy exploring their personality and how it might relate to blood type. One study showed that 99% of Japanese people know their blood types, though it’s important to note that it’s common for many people, regardless of ethnicity, to know their blood type for medical reasons. Nonetheless, the Japan Times has embraced this old, fun theory and has written popular articles on how the primary blood types indicate personality traits.

Read on to learn more about blood type personality traits and what your blood type personality might say about you!

Japanese Professor Tokeji Furukawa Advances Blood Type Personality Theory

The idea of blood type influencing one’s personality isn’t restricted to Japan and may not have even originated there. According to an article in Scientific American magazine, ancient philosophers such as Hippocrates and Aristotle explored the notion of a person’s personality based on different blood types. The article goes on to say that Japanese Professor Tokeji Furukawa chose blood as a physiological characteristic that could be classified according to blood types. His work was the basis for 204 publications by other researchers that discuss the connection between blood types and personality.

There are four primary blood types – A, B, A/B, and O. According to personality theory, the type of blood you have indicates the type of person you are, and the type of blood you have directly correlates to one of four personality types.

Are you curious about your blood type and how it connects to blood typing personality theory? Below, we explore what your blood type might say about you based on current bloody type personality theory. It’s important to note that, again, the below is not backed by consistent data and should be considered more of a fun idea to explore rather than absolute markers of personality or individual identity. Everyone exists on a spectrum, and none of us can be summed up or defined simply by our blood type. As you read this, you are likely to identify with all or multiple of the descriptions to some degree or another regardless of your blood type.


People with blood type A may be clever, passionate, sensitive, and cooperative. They can be loyal and patient, and they love peace. Sometimes, they may be overly sensitive about different things as compared with other blood types. For instance, they might care a lot about etiquette as well as social standards. According to blood type personality theory, A-personalities do not like to break the set rules on etiquette or the societal standards or rules that have been laid down. On occasions where they choose to break the rules, it’s considered a self-fulfilling prophecy.

A blood type personalities are considered careful decision-makers, and they can be known to take their time before they can settle on any decision. Moreover, they are not good at multi-tasking, as they prefer to handle one task at a time. Blood type A people are very organized, and they may not like haphazard actions. These blood type personalities prefer to keep everything neat and in the right place. In fact, they may go to great lengths to keep things neat and tidy. They might plan everything, and every task they engage in is carried out with a lot of consistency and seriousness. Many people with OCD fall may into this category and may benefit from seeking help from a professional counselor who can help with overcoming obsessive-compulsive behaviors, if desired.

People in this blood type category may be very stubborn and easily stressed. They may have higher levels of the stress hormone cortisol, and this makes them intense. They do not like fights and prefer to be in harmony with everyone, and they like to work in collaboration with others in the community. They tend to keep to themselves more so when they do not want to their ideas or opinions. Some of the most common traits of blood type A are as follows – blood type A people are kind, shy, stubborn, attentive, composed, polite, tense, withdrawn, reliable, perfectionistic, sensitive, responsible, tactful, timid, mild-mannered, anxious, earnest, reserved, and polite. As friends, people with type A are considered very reliable and trustworthy. If you are in trouble, you can rely on friends with this blood type. They may not like to show their emotions; they keep their thoughts or feeling about things hidden from others, and they only when comfortable. Famous people with blood type A are George Bush, Jet Li, Britney Spears, and Richard Nixon.


People with this blood type may be more likely to be creative individuals. Individuals who have B blood may make their decisions very quickly, and they are not good at taking orders. When type B blood people focus on something, they put their all into it, and they are unlikely to let go, even if the goal is unachievable or impractical. People with this blood type can have a very strong drive or desire to be the best at anything that they have set their minds to do. Nevertheless, according to blood type personality theory, people with this blood type are poor at multitasking. They are likely to neglect other important tasks and put all their focus on whatever they have set their mind on at the moment.

Learn More About The Four Blood Types And Their Associated Personality Traits

Click Here To Get Matched With A Licensed Therapist

B blood type people might face a lot of discrimination because of their potential negative personality traits, such as a possible tendency to be more selfish or uncooperative and stubborn at times. Society mainly focuses on the negative side of people with blood type B, even though people with this blood type (like any person) have many good qualities, too. As a result, they may tend to be loners, and may isolate themselves from others more so than other blood types. Blood type personality theory states that they may tend to approach things at their own pace. Some of the most common positive traits of people with blood type B include curiosity, relaxed, strong, adventurous, creative, passionate, active, outgoing, and cheerful. On the other hand, the negative traits can include being “wild,” erratic, unforgiving, selfish, uncooperative, irresponsible, and unpredictable. Bs are generally a balance of As and Os, as they are both thoughtful and ambitious. Famous people with type B are Vince Young, Leonardo DiCaprio, and Jack Nicholson. People with blood type B are more compatible with fellow blood type Bs, but they can also relate well with blood type ABs.


Blood type AB, based on the theory, is a mix of A and B personality types. People consider AB people complicated and double-sided. For instance, they can be outgoing just like Bs but may also be shy. At times, people view this blood type as having doublepersonalities, and they keep their true personalities from strangers. It is hard for a stranger to instantly decide which personality people with type AB have until they get to know them. People with this blood type are considered the rarest in the world. AB blood type people are empathetic, and they are likely to be careful when dealing with others. They make sure that they consider other people's points of view. These people have exceptional logical and analytical skills, and they are seen as humanists.

Some of AB’s blood type’s good traits can include being caring, charming, controlled, dependable, cool, composed, sociable, dream chaser, trustworthy, rational, creative, adaptable, and diplomatic. Their negative traits can include being self-centered, irresponsible, vulnerable, indecisive, forgetful, unforgiving, and critical. Famous people with AB are Barack Obama, Marilyn Monroe, Jackie Chan, and John F. Kennedy.


People with blood type O are considered to be outgoing, go-getters, and daring. Blood type personality theory states that they usually set high standards for themselves, and they do all they can to achieve them. Blood type Os have excellent leadership capabilities. Little things do not concern them, and this may make them appear selfish to people in blood group A who may be overly sensitive. Some of the positive personality traits in people with blood type O are: leadership ability, self-determined, easygoing, optimistic, calmness, confidence, outgoing, loyal, cautious, passionate, peaceful, resilient, independent, trendsetter, reliable, carefree, and devoted. On the negative, they are also jealous, rude, ruthless, insensitive, unpunctual, unpredictable, cold, self-centered, workaholics, and arrogant. Individuals with blood type O are very enduring and strong, and that is why the Japanese call them warriors. They are honest people and hate people who tell a lie or hide the truth. People who are O are not overly cautious about small details, as they tend to focus more on the big picture. Famous people with blood type O are such as Queen Elizabeth II, Paul Newman, Elvis Presley, Ronald Regan, John Gotti, and Gerald Ford.

Here is an easy reference guide for making compatibility decisions based on blood type theory:

  • Blood type O is compatible with AB and O blood types.
  • Blood type A is compatible with AB and A blood types.
  • Blood type B is compatible with AB and B blood types.
  • Blood type AB is compatible with all blood types.

Medical Concerns Regarding Blood Typing

While blood typing has been somewhat studied as a form of social psychology, scientific research and peer reviewed studies have primarily explored how blood type and the immune system works in connection with diseases such as cardiac disease and stomach cancer. Blood typing may help identify an increased risk of heart disease depending on a person’s blood type. Heart disease is particularly concerning for pregnant women who may have weaker immune systems depending on their blood types. Furthermore, various blood types have also been connected to an increased risk of stomach cancer. The number of a person’s red blood cells is directly related to the strength of a person’s immunity against bacteria and infections. New research shows that red blood cells are immune sensors in our bodies which could be a clue for diagnosing infections in critically ill people.

In pregnant women, the heart has to work harder, causing stress to the heart and blood vessels. There is an increase in blood volume and cardiac output which increases a pregnant woman’s heart rate. At the same time, blood pressure can decrease during pregnancy, causing a pregnant woman to feel short of breath and light-headed. According to the Harvard School of Public Health, women who have blood types A, B, or AB have an increased risk of cardiac disease. In relation to cancer and blood typing, one study found that people with type A blood had an increased risk of stomach cancer while people with type O blood had a slightly decreased risk of stomach cancer. The reason is that people with blood type A are more prone to H. pylori infections.

Regardless of your blood type, whenever you have a serious physical condition, it can impact your mental health. If this occurs, a licensed therapist can help you cope with trying times.

Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health

Blood Type Personality Conclusion

Final Thoughts And Things To Consider

Blood type personality theory is a fascinating topic that can make for interesting discussions in any circle. That said, personalities aren’t always easy to understand. If you’re struggling to understand your own personality or the personality of someone you care about, a licensed therapist can help you sort things out. If you're interested in learning more about yourself to improve, therapy is a great option. BetterHelp offers convenient and confidential therapy at an affordable price.

Start therapy online today.

Below are some commonly asked questions about blood type personality:
Which blood type has the best personality?
What is the personality of type A blood?
What blood type is common among psychopaths?
Which blood type is smart?
What is the strongest blood type?
Which blood group should not marry?
Is blood type A+ good?
Can O and A+ have babies?
What is the best blood type in Japan?
Which blood Cannot have babies?

Learn More About It

If you're interested in exploring potential links between your own blood type and personality, therapy may be a good place to start. Therapy is a personal experience, and not everyone will go into it seeking the same things. Keeping this in mind can ensure that you will get the most out of online therapy for blood type or blood personality type, regardless of what your specific goals are. If you’re still wondering if therapy for blood type analysis is right for you, and how much therapy costs, please contact us at [email protected] BetterHelp specializes in online therapy to help address all kinds of mental health concerns. If you’re interested in individual therapy, please reach out to [email protected] 

Where can I find more information about BetterHelp as a company and personality theory?

  • Pinterest
  • LinkedIn
  • Twitter
  • Instagram
  • Facebook

For more information on mental health, please see:

    • SAMHSA (Substance Abuse and Mental Health Services Administration) SAMHSA Facebook, SAMHSA Twitter, SAMHSA LinkedIn, SAMHSA Youtube
    • Mental Health America, MHA Twitter, MHA Facebook, MHA Instagram, MHA Pinterest, MHA LinkedIn
    • WebMD, WebMD Facebook, WebMD Twitter, WebMD Instagram, WebMD Pinterest
    • NIMH (National Institute of Mental Health), NIMH Instagram, NIMH Facebook, NIMH Twitter,NIMH YouTube
    • APA (American Psychiatric Association), APA Twitter, APA Facebook, n, APA Instagram

Blood Personalities, Personal Research, Blood Personality Theory, Personal Science, Personal Health, Personal Fitness, Personal Cultural Information, And Lifestyle Related Articles 

    • What Is Solution-Based Therapy?
    • Benefits Of Behavioral Therapy
    • What Are The Different Types Of Therapy Available?
    • What Is Group Therapy And How Effective Is It?
    • Talking Therapies: How Talk Therapy Can Help You In Treatment
    • Client-Centered Therapy: Why It Works
    • Counseling For Couples - How Does Couples Therapy Work?
    • What Is Family Therapy And Why Is It Beneficial?
    • Is Phone Counseling/Therapy Appropriate?
    • Couples Therapy: How Much Does Couple Counseling Cost?
    • Individual Counselling: One-On-One Talk Therapy
    • CBT Therapy – A Breakdown
    • Why Online Psychotherapy Is Becoming So Popular
    • Is Online Therapy Chat Effective?
    • Have Therapy Questions? We Can Help Answer Them
    • Which Is Better? The Psychotherapy Vs Counseling Debate
    • Couples Conflict: How Online Couples Therapy Can Help
    • Free Online Therapy vs Affordable Counseling. Find Out Why is BetterHelp Therapy Not Free?
    • Benefits Of Mindfulness Therapy In A Frantic World

What’s your blood group? The answer might reveal some interesting things about you

Back to Top

Now Reading:

What’s your blood group? The answer might reveal some interesting...

Share fbsharetwsharepinshareComments (0)

TNN | Last updated on -Apr 24, 2019, 15:34 ISTShare fbsharetwsharepinshare
Comments (0)


01/8​What’s your blood group?

In many countries, including India, people usually take a close look at a potential partner’s star sign to check their compatibility level. But the Japanese like to do things a little differently. They do not rely on the astrological information and signs alone, rather on the blood type for personality matching and information. Yes, your blood group can reveal your personality type!


02/8​Personality according to the blood type. What is it?

Ketsueki-gata is the term which means analyzing a person’s personality based on their blood type. The term gained popularity since the 1930s, thanks to Japanese professor Tokeji Furukawa who published a paper claiming that each blood type reflected the personality of a person who possessed it.


03/8​Science behind it

The four primary blood types, A, B, O and AB are differentiated from each other based on their antigens. Antigens are found at the surface of the red blood cell and help explain how effectively your immune system works.

You will be surprised to know that in Japan people are very fond of asking the blood type of other people because they truly believe in blood type personality theory. Japanese people use it as a tool to assess the potential of an employee and the compatibility of two people getting married.

Though the blood type personality test has no scientific backing yet, many people claim that it is absolutely true for them. Read on to know if Furukawa’s theory fits for you:


04/8​A blood type personality

People with A blood type are sensitive, cooperative, emotional, passionate and clever. They are very patient, loyal and love peace and thus do not like to get into a fight with anyone. But sometimes these people become overly sensitive. They do not like to break the rules set down by society and care about etiquette and social standards.

These people take their time to make decisions and are too organized in all spheres of life but cannot multitask. They like things neat and clean and at the right place, which is why many people with OCD fall into A blood type.

People with this blood type also get stressed easily and thus have a high level of cortisol (stress) hormone.

Common personality traits: Kind, shy, attentive, stubborn, polite, tensed, reliable, overly sensitive, perfectionist, responsible, timid, anxious, composed and reserved.

Best personality traits: Loyal, perfectionists, organized and consistent.

Bad personality traits: Obsessive, overly sensitive, pessimistic, stubborn, easily stressed and fastidious.

These people make reliable and trustworthy friends. They do not like to show their emotions and feeling to anyone unless comfortable with them.


05/8​B blood type personality

These people are very creative and quick decision makers. But they are not good at taking orders. They put every part of themselves into something they want to focus on. They have a very strong desire and drive to be the best of everything they do. But just like the A blood type, these people are also not good at multi-tasking.

People with B blood type are thoughtful and empathetic towards others and make good and reliable friends. These people also face a lot of discrimination because of their negative personality traits such as selfishness and being uncooperative at times. The society also focuses on the negative side of the people with B blood type, even though they have a good side too. But as a result of this, they tend to be loners.

Positive personality traits: Curious, strong, relaxed, creative, adventurous, passionate, cheerful, active and outgoing.

Negative personality traits: Wild, erratic, selfish, unforgiving, uncooperative, irresponsible and unpredictable.


06/8​AB Blood type personality

People with AB blood type are a mix of A and B personality types, just like their blood group. These people are complicated and can have dual personalities like they can be shy like A type as well as outgoing like B type. They try to keep their true personalities from strangers, thereby making most believe that they are a mixed personality. It is hard to decode these people until you know them thoroughly. Also, these people are the rarest blood type in the world.

They are charming and make friends easily. There will never be a dull moment in a group of friends even if only one of them is AB blood type. They are poor at handling stress.

AB people are very careful while dealing with others and are empathetic. These people also have exceptional analytical and logical skills.

Good personality traits: Charming, controlled, cool, dream chaser, caring, rational, trustworthy, adaptable and creative.

Negative personality traits: Complicated, vulnerable, irresponsible, self-centered, forgetful, unforgiving and critical.


07/8​O Blood type personality

People with O blood type are daring, outgoing and go-getters. They have a habit of setting high standard for themselves and do all they can to achieve them. These people have excellent leadership qualities and little things do not bother them, which makes them appear as selfish to other people, especially to A type.

They are generous, kind-hearted and loving. They adapt well with changes. They are resilient and flexible and can do better than other blood types in tough situations.

Positive personalities traits: Leadership, easy going, positive outlook, confident, calm, outgoing, cautious, loyal, peaceful, passionate, independent, reliable, carefree, trendsetter and devoted.

Japanese people call people with O blood type, warriors because they are strong and enduring. These people are honest and hate people who hide the truth.

Negative personality traits: Jealous, ruthless, rude, non-punctual, insensitive, cold, unpredictable, self-centered and arrogant.


08/8​Easy guide to make compatibility decisions

O blood type is compatible with AB type and O type

A blood type is compatible with AB type and A type

B blood type is compatible with AB type and B type

AB blood type is compatible with all the blood groups


Blood types: why they are different and how they affect our diet and disease

  • Carl Zimmer
  • BBC Future

Photo credit, Science Photo Library

more than

century after their discovery we still don’t know why we have different blood types, how they arose, and whether the popular blood type diets actually work.

When my parents told me that my blood type was A+, or A+, I felt a surge of pride. After all, "A" is an excellent grade at school, which means that I got the best blood.

I quickly learned that there was nothing to be proud of, but what "second positive blood type" actually means remained a mystery to me.

Even when I grew up, all I knew about blood types was that if I needed a transfusion, the doctors would have to find blood for me that was compatible with mine.

The difference in blood types is shrouded in many secrets. Why is it that 40% of whites have type II (or A) blood, while among Asians this figure is only 27%? How did different types of blood come about and why are they needed?

And then I decided to ask the experts - hematologists, geneticists, evolutionary biologists, virologists and nutrition researchers.

Photo credit, Science Photo Library

Photo caption,

Everyone knows that blood type differs from person to person, but why this is so is still unknown

In 1900, the Austrian physician Karl Landsteiner first discovered the existence of In 1930 he received the Nobel Prize in Physiology or Medicine for this discovery.

Since then, scientists have developed powerful tools for studying blood types. They were able to trace the evolution of their development and find out their impact on health. However, much remains unclear.

For example, why they exist at all is still unknown.

Life-threatening transfusion

The fact that we know our blood type is one of the most important discoveries in the history of medicine. Thanks to him, doctors can now save lives by transfusing blood to patients.

But for most of history, the question of whether it is possible to infuse the patient with the blood of another person caused confusion among the Aesculapius.

Some of them believed that transfusion could cure all diseases and even insanity. And in the 1600s, several physicians tested the idea. Not surprisingly, with tragic results.

This ruined the reputation of blood transfusion for a long time. Even in the 19th century, many did not dare to do this procedure. The exception was the British physician James Blundell.

He saw his patients die of massive blood loss during childbirth and decided he couldn't take it anymore.

Photo credit, Science Photo Library

Photo caption,

Blood transfusions only became commonplace after scientists discovered blood types kind. Patients should receive only human blood, the scientist insisted.

Blundell soon tried to test his theory in practice. He transfused the patient with 0.4 liters of blood received from donors. At first the patient felt much better, but died two days later.

This did not stop Blundell, he believed that blood transfusion would be of great benefit to mankind and continued his experiments. In the following years, he gave 10 more blood transfusions, and only four of his patients survived.

Some other doctors have also experimented with blood transfusions (some have even tried adding milk to the blood), but the results have generally not been very encouraging.

Unexpected discovery

Blundell was right that only the blood of another person can be transfused, but he did not know that not all people's blood is compatible. This fact soon became known thanks to a fairly simple procedure.

When scientists tried to mix different people's blood in a test tube in the late 1800s, they noticed that it sometimes clotted. At first, no one paid attention to this, since the reason for this was considered to be that the blood in the test tube was from sick people.

For the first time, Karl Landsteiner thought about this, who began to study the patterns of clots, mixing the blood of healthy people, including his own.

In each sample, he separated the red blood cells from the plasma and then added the red blood cells of another person to the plasma of one person.

Photo credit, Science Photo Library

Photo caption,

Karl Landsteiner discovered blood types by experimenting with samples of his blood and those of his colleagues

Landsteiner saw that clotting only occurred when the blood of certain people was mixed, and by research he discovered three main groups. He named them A, B, and C. Subsequently, the C group was renamed O, and a few years later, researchers also discovered the AB group.

(In the former USSR, the I-IV numbering system was used according to Jansky, a Czech scientist who discovered blood groups independently of Landsteiner and almost simultaneously with him. - Ed. )

blood, depending on whether it has the Rh factor (Rh).

To indicate this feature, Landsteiner's classification began to add a plus or minus sign.

What is the difference

It is this thickening of the blood that makes it potentially dangerous to transfuse.

If a doctor accidentally injects me with type 3 (B) blood, tiny clots will appear in my circulatory system. They will cut off blood circulation and cause heavy bleeding, I will have difficulty breathing and I could die.

But if I get type 2 blood (like my own) or type 1, everything will be fine.

Landsteiner did not know what exactly distinguished blood types. This was found out by the next generations of scientists. They found that each group of red blood cells had different molecules on their surface.

For example, in my blood of the second group, these molecules consist of two parts, like the floors of a house. The first floor is called the H antigen, and the second - the A antigen.

In people with the third blood group, this second floor is formed differently, but with the first group - it does not exist at all, that is, only the H antigen exists.

Photo by Science Photo Library

Photo caption,

Different blood types are the result of different molecular structures on the surface of red blood cells.

Every person's immune system is familiar with its blood type. However, if a person receives a transfusion of the wrong type of blood, their immune system will go berserk.

The exception is the blood of the first group (O). It has only H antigens, which are also present in other blood types, and therefore such blood is compatible with other groups. That is why people with the first blood group are universal donors, and their blood is primarily valuable for blood transfusion stations.

Blood type diet

Skip the podcast and continue



End Podcast

In 1996, the naturopath Peter D'Adamo published the book The Blood Type Diet. The doctor argued that we should adjust our diet according to the blood type and thus bring our body into harmony with its genetic heritage.

He argued that blood groups arose at critical moments in the evolution of mankind. The first is among hunter-gatherers in Africa, the second is at the dawn of the agricultural revolution, and the third is some 10,000 or 15,000 years ago in the Himalayas.

The fourth group (AB) arose as a result of a fairly recent mixture of the second and third.

Based on this, D'Adamo suggested that our blood type should determine our nutrition. Since my second group originated with the advent of agriculture, I must be a vegetarian.

People with ancient hunting type O (group I) need to eat a lot of meat and avoid grains and dairy products. As the author of the book notes, food that is incompatible with our blood type contains antigens that cause various diseases.

D'Adamo recommended his diet as a way to reduce the risk of infections, lose weight, prevent cancer and diabetes, and slow down the aging process.

Photo credit, Science Photo Library

Photo caption,

Test cards with samples are used to determine the patient's blood type and diet

Doctor D'Adamo's book has sold 7 million copies and has been translated into 60 languages. Since then, a number of similar studies have appeared, and as a result, doctors are often asked if the blood type diet actually works.

The answer to this question turned out to be quite simple. Back in Blood Type Diets, D'Adamo wrote that he was conducting a ten-year experiment in which he was testing the effectiveness of the diet in women with cancer.

At the time of publication of the book, the experiment was already in its eighth year, but 18 years later, the results of this study have not been made public.

Recently, researchers from the Belgian Red Cross also decided to find out if there was any objective evidence in favor of these diets.

They reviewed the scientific literature and found over a thousand studies in this area. However, none of them supported Peter D'Adamo's theory.

Despite this, some people who follow the Blood Type Diet still see positive results.

According to University of Toronto nutrition expert Ahmed El-Sohemi, they have nothing to do with blood type, but can be explained by the universal principles of healthy eating.

Photo credit, Science Photo Library

Photo caption,

Scientists believe that the theory that blood type can determine diet is unfounded.

The benefit of the blood type I diet is that it provides for a significant reduction in carbohydrate intake. But a diet that consists predominantly of dairy products is not healthy for anyone. And blood type doesn't matter.

The question of origin

However, the blood type diet theory raises another interesting question. Why do we have different blood types?

After Landsteiner made his landmark discovery in 1900, scientists immediately became interested in whether blood types differed in animals as well.

It turned out that the blood of some primates is compatible with certain blood types of humans. But the fact that a monkey can have blood of the second type, like me, does not necessarily mean that we have inherited the same gene from a common ancestor.

Blood of the second group could have arisen several times in the course of evolution.

Something began to emerge in the 1990s when scientists began to study blood types using molecular biology.

They found that a single gene called ABO is responsible for the construction of the second floor in molecules on the surface of red blood cells. Version A of this gene differs from version B (that is, the second blood type from the third) by several key mutations.

And in people with the first group (O), mutations in the ABO gene have occurred that prevent the formation of an enzyme that builds antigen A or B.

Photo credit, Science Photo Library

Photo caption,

Our blood has more in common with gibbon blood than one might think

By comparing the ABO gene in humans and other animal species, the researchers found that the division into different blood types arose a long time ago. Gibbons and humans have variants of the second and third blood types, which are descended from a common ancestor who lived 20 million years ago.

Our blood types may have originated even earlier, but it is rather difficult to find out the exact time. To do this, scientists need to analyze the genes of all primates.

However, the data already collected by scientists show that the evolution of blood types has been very turbulent. Due to mutations, some of the blood types of our direct relatives have disappeared.

So, chimpanzees have only the first and second blood groups, and gorillas, on the contrary, only the third.

In some cases, mutations change the ABO gene, turning the blood of the second group (A) into the third (B). And even in humans, mutations in the genes can prevent the creation of a second floor in the molecules of red blood cells, and thus turn the blood of the second or third group of the first.

The Bombay Phenomenon

The fact that we still do not understand why nature created different blood types was best confirmed in Bombay in 1952.

Doctors in this Indian city unexpectedly discovered a group of patients who had no blood type at all.

If the second and third groups have molecules in the form of two-story buildings, and the first - one-story buildings, then in these Bombay patients, the surface of the erythrocytes was empty.

This strange case has been called the "Bombay phenotype". Later it was found in other people, although this type of blood is extremely rare. As far as scientists know, such blood does not carry any risks for its owner, except for a single situation.

If a person with the Bombay phenotype needs a blood transfusion, only the same type of blood will be accepted. Even the first blood group, which is considered compatible with all the others, will be deadly for such a patient.

Image copyright, Getty Images

Image caption,

In the 1950s, doctors in Bombay discovered a group of patients who had no blood type at all. .

Some scientists, however, believe that the evolutionary meaning lies in the variety of types, since different blood types can protect against different diseases.

Doctors first began to notice the link between blood type and various diseases in the middle of the 20th century, and the list continues to grow.

So, to my displeasure, I learned that the second blood type (A) increases the risk of several types of cancer, in particular pancreatic cancer and leukemia. Because of my blood type, I am also more prone to smallpox, heart disease, and a severe type of malaria.

But carriers of groups I, III and IV may face other problems. For example, people with type I blood are more likely to have ulcers and rupture of the Achilles tendon.

Involvement of viruses

Scientists are just beginning to figure out the reasons for this connection. They were able, for example, to find out why people with the first blood type are better protected from a severe type of malaria than people with other blood types.

It turns out that immune cells in the blood of the first group detect infection faster.

More mysterious is the relationship between blood type and diseases that are not related to the circulatory system, such as norovirus infection.

This nasty pathogen is a real scourge on cruise ships, as it can cause severe intestinal infections in hundreds of passengers at the same time.

Image copyright Science Photo Library

Photo caption,

Your blood type determines how susceptible you are to infections such as norovirus

Norovirus enters the cells that line the intestines, but does not affect blood cells. However, people with a certain blood type are less likely to be infected with norovirus.

The explanation for this particular mystery may lie in the fact that antigens of a certain blood type are produced not only in the blood, but also in the walls of blood vessels, the respiratory tract, and even skin and hair.

The point is that the norovirus strongly "attaches" only to those cells whose proteins are compatible with the antigens of a certain blood group.

And it also sheds some light on why different blood types have not disappeared over millions of years of evolution.

Our primate ancestors were in constant contact with countless viruses, bacteria and other invisible enemies. Some of these pathogens adapted to the antigens of the most common blood group and gradually destroyed its owners.

While primates with a rarer blood group survived during such epidemics.

When I think about all this, my second blood type seems to me as mysterious as it was when I was a child. But in this mystery for me now there is a certain pleasure.

I understand that the explanation for why I have this particular blood type goes beyond my circulatory system.

Read this article in English 0084 on the site E BBC Future

blood group

Inheritance of blood group by a child

Often in the maternity hospital the question is as a question: "What is my child’s group?" And then they think for a long time and painfully: “why did they say that my baby has the first blood type, if my husband and I have the second?”.

To answer this question, let's remember what blood groups are and what laws of nature they "obey".

At the beginning of the last century, scientists proved the existence of 4 blood groups.

Austrian scientist Karl Landsteiner, mixing the blood serum of some people with erythrocytes taken from the blood of others, found that with some combinations of erythrocytes and serums, “gluing” occurs - erythrocytes stick together and form clots, while others do not.

Studying the structure of red blood cells, Landsteiner discovered special substances. He divided them into two categories, A and B, highlighting the third, where he attributed the cells in which they were not. Later, his students - A. von Decastello and A. Sturli - discovered erythrocytes containing both A- and B-type markers at the same time.

As a result of research, a system of dividing by blood groups arose, which was called ABO. We are still using this system.

  • I ( 0 ) – blood group is characterized by the absence of A and B antigens;
  • II ( A ) - is established in the presence of antigen A;
  • III (AB) - antigens B;
  • IV( AB ) - antigens A and B.

The AB0 system turned scientists' ideas about the properties of blood upside down. Their further study was carried out by genetic scientists. They proved that the principles of inheritance of a child's blood type are the same as for other traits. These laws were formulated in the second half of the 19th century by Mendel, based on experiments with peas familiar to all of us from biology school textbooks.

So how are inherited by a child of blood types according to Mendel's law?

  • According to the laws of Mendel, parents with I blood group will have children who do not have A- and B-type antigens.
  • Spouses with I and II have children with the corresponding blood types. The same situation is typical for groups I and III.
  • People with type IV can have children with any blood type except I, regardless of what type of antigens their partner has.
  • The most unpredictable is the inheritance of a blood group by a child in the union of owners with groups II and III. Their children can have any of the four blood types with the same probability.
  • An exception to the rule is the so-called "Bombay Phenomenon". In some people, the A and B antigens are present in the phenotype, but do not appear phenotypically. True, this is extremely rare and mainly among the Indians, for which it got its name.





I (100%)




I + II

I (50%)

II (50%)




I (50%)


III (50%)




II (50%)

III (50%)



I (25%)

II (75%)




I (25%)

II (25%)

III (25%)

IV (25%)



II (50%)

III (25%)

IV (25%)


I (25%)


III (75%)




I (25%)

III (50%)

IV (25%)



II (25%)

III (25%)

IV (50%)


The birth of a child with a negative Rh factor in a family of Rh-positive parents causes deep bewilderment at best, distrust at worst. Reproaches and doubts about the fidelity of the spouse. Oddly enough, there is nothing exceptional in this situation. There is a simple explanation for such a delicate problem, which is based on all the same laws of genetics.

Rh factor is a lipoprotein located on the membranes of red blood cells in 85% of people (they are considered Rh-positive). In the absence of it, they speak of Rh-negative blood. These indicators are denoted by the Latin letters Rh with a plus or minus sign, respectively.

The gene for the positive Rh factor is designated D, it is a dominant trait (always appears). The Rh negative gene is recessive and is designated d (only appears in the absence of D). Therefore, in people with a set of chromosomes DD or Dd, the blood will be Rh positive, and only with a set of chromosomes dd - Rh negative.

Therefore, parents with a homozygous lack of Rh factor (dd) can only give birth to children with Rh negative blood.

Homozygous Rh positive (DD) parents will only have children with Rh positive blood.

But with the union of people with Rh positive blood belonging to the presence of heterozygous Rh (Dd), their children will be positive in 75% of cases and negative in the remaining 25%.

So, parents: Dd x Dd. Children: DD, Dd, dd - here they are Rh negative children of Rh positive parents.! .

Inheritance of the blood group of the Rh system, possible in a child, depending on the blood groups of his parents.

Blood type

Father's blood type



Child's blood type






Rh negative

And a little more interesting stuff from geneticists…


For centuries, parents only wondered what their child would be like. Today there is an opportunity to look into the future. Thanks to ultrasound, you can find out the sex and some features of the anatomy and physiology of the baby.

Genetics, on the other hand, will determine the probable color of the eyes and hair, and even the presence of an ear for music in a baby. All these traits are inherited according to the laws of Mendel and are divided into dominant and recessive.

Brown eyes, hair with small curls, the ability to roll the tongue into a tube are dominant features. Most likely, the child will inherit them. Unfortunately, the dominant features also include a tendency to early baldness and graying, myopia and a gap between the front teeth.

Gray and blue eyes, straight hair, fair skin, mediocre ear for music are considered recessive. These symptoms are less likely to occur.


For many centuries, the blame for the absence of an heir in the family was placed on the woman.

Learn more