The Bible’s Viewpoint

Is Your Personality Determined by Blood Type?

ASSESSING someone’s personality based on his or her blood type is popular in some countries. In Japan, for example, it is not unusual for some to ask, “What’s your blood type?” as a conversation starter. Advocates of this idea claim that people with type A blood are calm, responsible, and suspicious; those with type B blood are openhearted, moody, easily deceived; and so forth. It is also asserted that a person of one blood type may find it difficult​—or easy—​to get along with someone of another blood type.

Based on this concept, some consider blood type to be an important factor when grouping students in schools, selecting executives at companies, or even choosing mates. Is there any proof that our blood type really determines our personality? Are there any Bible teachings that touch on this matter?

What Is Blood Type?

The World Book Multimedia Encyclopedia explains: “The membranes of red blood cells contain proteins called antigens. More than 300 red-cell antigens have been identified.” While some people have certain antigens, others do not, and some antigens cannot coexist. Therefore, as the encyclopedia adds, “based on the presence or absence of particular antigens, scientists have classified human blood into various groups.”

The most widely accepted blood-grouping system is the ABO system, which classifies human blood into four types​—A, B, AB, and O. In addition, the Rh system is commonly used. Actually, there are some 20 known  blood-grouping systems. Obviously, then, blood is very complex. The Encyclopædia Britannica states: “The large number of different red cell antigens makes it extremely unlikely that persons other than identical twins will have the same array of blood group substances.”

This suggests that, precisely speaking, everyone has a unique “blood type.” Claiming that people with certain blood types share personality traits thus seems to have little foundation. A number of factors evidently determine our personality.

What Determines Our Personality?

“Personality is those behavioral characteristics, both inherent and acquired, that distinguish each individual,” explains the Encyclopædia Britannica. Yes, in addition to what we have inherited, there are other factors​—such as family environment, education, association, and experiences both good and bad—​that affect our personality development. Therefore, our genetic makeup is not all that determines our personality. Even identical twins, who have the same genetic makeup, often have different personalities.

Another important fact is that one’s personality can change or be changed. The apostle Paul emphasized the power of Christian teachings to change people. He wrote: “Strip off the old personality with its practices, and clothe yourselves with the new personality, which through accurate knowledge is being made new according to the image of the One who created it.” (Colossians 3:9, 10) Christians recognize that they are sinners and have inherited sinful tendencies. For them to be accepted by God, their personalities had to be transformed.

What makes such changes possible? It is the power of God’s word, or message. Regarding the strong influence of God’s word, now found in the Bible, Paul wrote: “The word of God is alive and exerts power and is sharper than any two-edged sword and pierces even to the dividing of soul and spirit, and of joints and their marrow, and is able to discern thoughts and intentions of the heart.” (Hebrews 4:12) When an individual yields to the influence of God’s spirit and tries to conform to the moral standards set out in the Bible, his personality can gradually change. The Christian personality formed in this way includes “the tender affections of compassion, kindness, lowliness of mind, mildness, and long-suffering.”​—Colossians 3:12.

Christian Reasonableness

Granted, there is no Bible principle that prohibits the study of blood types. But any relation this might have to human behavior is another matter. As with all things in life, we must let God’s Word guide our steps. (Psalm 119:105) Reasonableness is also vital.​—Philippians 4:5.

It would certainly be unreasonable to use one’s blood type as an excuse for not trying to correct personality flaws. Regardless of their genetic makeup, Christians must continue to make progress in molding their personality to reflect the qualities of Jehovah and Jesus as much as possible.​—Ephesians 5:1.

In addition, Christians strive to view others in the way Jehovah views them. “God is not partial.” (Acts 10:34, 35) Jehovah gladly accepts people of all sorts. So it would be unreasonable and unchristian to shun or avoid the company of certain ones simply because of their blood type. The same would be true if one was to associate exclusively with those who have a “compatible” blood type. The Bible admonishes: “If you continue showing favoritism, you are working a sin.”​—James 2:9.

As science and technology advance, there are many new findings and theories about the human body. It is natural to be fascinated by these concepts. Still, Christians do well to let the Bible​—not human theories—​guide their thinking. In all walks of life, Christians need to “make sure of all things” and “hold fast to what is fine.”​—1 Thessalonians 5:21.