Parent-to-Child Blood Group

Understand the biological inheritance of the ABO blood group and Rh factor systems from parent to child.

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Frequently Asked Questions — Parent-to-Child Blood Group

Why does my child have an O blood type when I have an A type?+

Blood type A can be either homozygous (AA) or heterozygous (AO). If you and your partner both carry the recessive "O" allele (i.e. you are AO and BO), your child has a 25% chance of inheriting both O alleles, resulting in type O blood.