Blood Type Calculator - Predict Child Blood Type
Parents' Blood Types
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Possible Blood Types
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Understanding Blood Type Genetics
Blood type inheritance follows predictable genetic patterns based on Mendelian genetics. Understanding how blood types are passed from parents to children can help you predict possible blood types for your offspring and understand blood compatibility for medical purposes.
The ABO Blood Group System
The ABO system classifies blood into four main types based on the presence or absence of A and B antigens on red blood cells:
- Type A: Has A antigens on red cells and anti-B antibodies in plasma
- Type B: Has B antigens on red cells and anti-A antibodies in plasma
- Type AB: Has both A and B antigens, no anti-A or anti-B antibodies (universal recipient)
- Type O: Has no A or B antigens, has both anti-A and anti-B antibodies (universal donor)
Genetic Inheritance Patterns
Allele Combinations
Each person inherits one ABO allele from each parent. Possible combinations:
- • AA or AO = Type A blood
- • BB or BO = Type B blood
- • AB = Type AB blood
- • OO = Type O blood
The Rh Factor
The Rh factor is a separate protein that can be present (+) or absent (-) on red blood cells. Rh positive is dominant over Rh negative:
- Rh+: Can have ++ or +- genotype
- Rh-: Must have -- genotype (two negative genes)
- Two Rh+ parents can have Rh- children if both carry the recessive gene
- Two Rh- parents can only have Rh- children
Blood Compatibility for Transfusion
| Blood Type | Can Donate To | Can Receive From |
|---|---|---|
| O- | All types (Universal Donor) | O- |
| O+ | O+, A+, B+, AB+ | O-, O+ |
| A- | A-, A+, AB-, AB+ | O-, A- |
| A+ | A+, AB+ | O-, O+, A-, A+ |
| B- | B-, B+, AB-, AB+ | O-, B- |
| B+ | B+, AB+ | O-, O+, B-, B+ |
| AB- | AB-, AB+ | O-, A-, B-, AB- |
| AB+ | AB+ | All types (Universal Recipient) |
Important Medical Considerations
Rh Incompatibility in Pregnancy
When an Rh- mother carries an Rh+ baby, her immune system may produce antibodies against the baby's Rh+ blood cells. This can cause hemolytic disease in subsequent pregnancies. RhoGAM injections prevent this complication by stopping antibody formation.
Blood Type Distribution
Blood type frequency varies by ethnicity and geography. In the United States:
- O+ is most common (37-38% of population)
- AB- is rarest (less than 1% of population)
- About 85% of people are Rh positive
- Type O is more common in Hispanic and African American populations