A child is born with type AB blood what blood must the parents have?

Answer 1

The most likely blood type for the child is A positive - but A negative, O positive and O negative are also possible depending on the genotypes of the parents.

If both parents are heterozygous AO, then the child could have either A or O type blood. If either parent is homozygous, AA, then the child must have blood type A.

If the parent with positive blood is heterozygous, Dd (+-), then the child could have either positive or negative type blood. If they are homozygous, DD (++), then the child must have positive type blood.

Answer 2

If a baby is blood type B, the one parent must have a B. The possible combinations are:

One parent B (homozygous or heterozygous), other parent B (homozygous or heterozygous)

One parent B (homozygous or heterozygous), other parent A (heterozygous)

One parent B (homozygous or heterozygous), other parent AB

One parent B (homozygous or heterozygous), other parent O

One parent AB (homozygous or heterozygous), other parent O (homozygous or heterozygous)

The Rh factor must be either positive heterozygous or negative in each of the parents.

Answer 3

If one parent is AB- and another parent is B-, then the possible bloodtypes of their child is as follows:

AB-

BB-

B- [or BO-]

A- [or AO-]

There would be an equal chance of any one of these genotypes from occurring.

Answer 4

Both parents are rhesus-negative and have a genotype of BX (X being any of A, B and O), but nothing else can be determined.

Answer 5

can both be AB or must be different and neither can be type O

Answer 6

Blood type B or Blood type O

Answer 7

A or O -