Blood Types Tutorial

How are ABO alleles inherited by our children?


Human ABO markers

Blood types and genotypes?

How are ABO alleles inherited by our children?

Blood type & Rh factor calculator

Blood type calculator

Rh factor

Problem set
Each biological parent donates one of their two ABO alleles to their child. A mother who is blood type O can only pass an O allele to her son or daughter. A father who is blood type AB could pass either an A or a B allele to his son or daughter. This couple could have children of either blood type A (O from mother and A from father) or blood type B (O from mother and B from father).

Inherited Blood type
of child
O from the mother
A from the father
O from the mother
B from the father

Since there are 4 different maternal blood types and 4 different paternal blood types possible, there are 16 different combinations to consider when predicting the blood type of children.

Blood Type Calculator

The following Blood Type Calculator lets you determine the *possible* blood type of a child, given the blood types of the two biological parents or the *possible* blood types of one biological parent, given the blood types of the child and the other biological parent. We emphasize "possible" because, in most cases, blood typing is not conclusive when attempting to determine, include or exclude an individual as the parent of an offspring.

This calculator is based solely on theoretical principles. It would be a mistake to use this information to make any conclusions about your own family tree. Anyone wishing personal information about their own blood type inheritance is encouraged to contact their health care provider.

Determine the *possible* blood types of the other biological parent

Child Blood TypeParent Blood Type

Determine the *possible* blood types for a child

Parent 1 Blood TypeParent 2 Blood Type

The Biology Project
University of Arizona
Monday, March 30, 1998
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All contents copyright © 1998. All rights reserved.