Blood Type / Genotype Calculator
Determine the probabilities of ABO blood types and Rh factor (+/-) inheritance for children based on parents' genotypes.
Parental Blood Types & Genotypes
Select the specific ABO and Rh factor genotype details for each parent.
Parent 1
Parent 2
ABO Punnett Grid
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Rh Factor Punnett Grid
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Offspring Blood Type Probabilities
Phenotype (Blood Group & Rh)
Genotype Breakdown
ABO & Rh Rules
ABO follows codominance (A and B) and recessive inheritance (O). Rh factor follows simple dominant (+) and recessive (-) inheritance.
ABO Blood Group Genotype vs Phenotype Matrix
| Blood Type Phenotype | Possible Genotypes | Red Cell Antigens | Plasma Antibodies | Can Receive Red Cells From |
|---|---|---|---|---|
| Type A | AA, AO (IAIA, IAi) | A Antigen | Anti-B | Type A, Type O |
| Type B | BB, BO (IBIB, IBi) | B Antigen | Anti-A | Type B, Type O |
| Type AB | AB (IAIB) | A and B Antigens | None | Universal Recipient (A, B, AB, O) |
| Type O | OO (ii) | None | Anti-A and Anti-B | Type O only (Universal Donor to all) |
Calculation Methodology & Biological Principles
Codominance & Recessiveness
In the ABO system, alleles A and B are codominant. When an individual inherits both (AB), both A and B surface antigens are co-expressed. The O allele is completely recessive.
Rh Factor Dominance
The Rh factor (D antigen) follows Mendelian complete dominance. DD and Dd produce Rh-positive (+), whereas dd produces Rh-negative (-).
Frequently Asked Questions
How is ABO Blood Type inherited? ▼
ABO blood type is controlled by a single gene locus with three alleles: IA (A antigen), IB (B antigen), and i (O, no antigen). IA and IB are codominant with each other, and both are completely dominant over the recessive i allele.
Can two Type A parents have a Type O child? ▼
Yes. If both Type A parents are heterozygous carrying the hidden recessive O allele (genotype AO x AO), there is a 25% (1 in 4) chance that their child will inherit two O alleles (genotype OO) and have Type O blood.
How does Rh factor (+/-) inheritance work? ▼
The Rh factor is inherited independently of ABO blood group. Rh-positive (+) is dominant (D), while Rh-negative (-) is recessive (d). An Rh-positive parent can be DD or Dd. If both parents are Dd (Rh+), there is a 25% chance of having an Rh-negative (dd) child.
Related Calculators
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Incomplete Dominance Calculator
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