| Blood type | Probability |
|---|---|
| A+ | 18.8% |
| B+ | 18.8% |
| AB+ | 18.8% |
| O+ | 18.8% |
| A- | 6.3% |
| B- | 6.3% |
| AB- | 6.3% |
| O- | 6.3% |
| ABO type | Probability |
|---|---|
| A | 25% |
| B | 25% |
| AB | 25% |
| O | 25% |
| Rh factor | Probability |
|---|---|
| Rh+ | 75% |
| Rh- | 25% |
Note: This calculator provides probabilities based on standard blood type inheritance patterns. Actual results may vary due to genetic factors. Consult a healthcare provider for medical advice.
If you've ever wondered what blood type is or what blood type your baby will have, this blood type calculator is for you. You'll be able to determine the possible blood types for your child based on the parents' blood types. Additionally, in this article, you'll find a comprehensive guide to understanding blood groups, compatibility, and inheritance patterns.
Blood types are classifications of blood based on the presence or absence of specific antigens on the surface of red blood cells. These antigens are proteins or carbohydrates that can trigger an immune response if they are foreign to the body.
The main blood group system is called ABO, which categorizes blood into four types:
Each blood type also contains antibodies in the plasma:
These antibodies are why blood transfusions must be carefully matched – if incompatible blood types are mixed, the antibodies will attack the foreign antigens, causing a dangerous reaction.
Blood type is inherited from your parents and remains the same throughout your life.
The Rh factor is another important blood classification system. It refers to the presence or absence of the Rh(D) antigen on red blood cells:
This creates eight possible blood type combinations:
The Rh factor is particularly important during pregnancy. If an Rh- mother carries an Rh+ baby, her immune system may produce antibodies against the baby's blood cells. This can lead to hemolytic disease of the newborn in subsequent pregnancies. Rh- mothers typically receive Rh immunoglobulin (RhoGAM) to prevent this complication.
Blood type follows Mendelian inheritance patterns. Each person has two alleles (gene variants) for blood type, one inherited from each parent:
The A and B alleles are codominant (both express equally), while the O allele is recessive (only expressed when paired with another O).
For the Rh factor:
The positive allele is dominant, so only one copy is needed for Rh+ blood type.
To determine possible blood types for your baby, follow these steps:
If one parent is blood type A (genotype AO) and the other is blood type B (genotype BO):
| Parent 1 → | A | O |
|---|---|---|
| B | AB | BO |
| O | AO | OO |
Results:
| Parent combinations | Rh+ child probability | Rh- child probability |
|---|---|---|
| Both Rh+ | 93.75% | 6.25% |
| One Rh+, one Rh- | 75% | 25% |
| Both Rh- | 0% | 100% |
This table shows all possible blood types a child can have based on the parents' blood types:
| Parent 1 | Parent 2 | Possible child blood types |
|---|---|---|
| O | O | O |
| O | A | O, A |
| O | B | O, B |
| O | AB | A, B |
| A | A | O, A |
| A | B | O, A, B, AB |
| A | AB | A, B, AB |
| B | B | O, B |
| B | AB | A, B, AB |
| AB | AB | A, B, AB |
Yes, absolutely! A child can have a different blood type than both parents. This happens frequently due to the way blood type alleles are inherited. Here are some examples:
The key is understanding the underlying genotypes, not just the phenotypes (observable blood types).
Understanding blood type compatibility is crucial for safe blood transfusions:
| Recipient | Can receive from |
|---|---|
| O- | O- only |
| O+ | O-, O+ |
| A- | O-, A- |
| A+ | O-, O+, A-, A+ |
| B- | O-, B- |
| B+ | O-, O+, B-, B+ |
| AB- | O-, A-, B-, AB- |
| AB+ | All blood types |
Key points:
Blood type distribution varies by ethnicity and geographic location. Here's the approximate distribution in the general population:
| Blood type | Frequency | Classification |
|---|---|---|
| O+ | 38% | Most common |
| A+ | 34% | Very common |
| B+ | 9% | Common |
| O- | 7% | Common |
| A- | 6% | Uncommon |
| AB+ | 3% | Rare |
| B- | 2% | Rare |
| AB- | 1% | Rarest |
The rarest blood types include:
💡 Rare blood types can make finding compatible donors extremely difficult. Some people with rare blood types bank their own blood for emergencies.
Certain blood types are associated with increased or decreased risks for various health conditions:
Type O:
Type A:
Type B:
Type AB:
These associations are statistical and don't guarantee any individual will develop these conditions.
Yes, if both O+ parents carry one positive and one negative Rh allele (+-), they have a 25% chance of having an O- child who inherits the negative allele from each parent.
If you donate incompatible blood, the recipient's antibodies will attack the donor's red blood cells, causing them to clump together (agglutinate) and break apart (hemolyze). This can cause kidney failure, shock, and death.
There's no "best" blood type, but O- is valuable as the universal donor, while AB+ recipients have the most donation options. Each blood type has evolutionary advantages and disadvantages.
Blood type typically remains constant throughout life. However, bone marrow transplants can change blood type if the donor has a different type. Some cancers and infections can also temporarily alter blood type expression.
No, siblings can have different blood types unless the parents' genotypes limit the possibilities. For example, if both parents are type O, all children will be type O. But if parents have different blood types, siblings may vary.
While blood type personality theory is popular in some cultures (particularly Japan), there's no scientific evidence linking blood type to personality traits. This is considered a pseudoscience.
Different blood types may provide resistance to various diseases. For example, type O individuals are more resistant to severe malaria, while other types may offer protection against different pathogens. This diversity helps human populations survive various disease threats.
Home blood typing kits are available, but for medical purposes, you should have your blood type determined by a certified laboratory. This ensures accuracy and proper documentation for medical records.