# The Blood Group of parents (both father & mother) is A+. Their female child blood group is A-. Is this possible?

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If the parents both carry the recessive gene form (allele) for the Rh gene then yes it is possible.

If dad was AA+- or Ao+- he could make a sperm cell that contained an A-. (possible sperm cells A+, A- in the first case & A+, A-, o+, o- in the second).

If mom also had either of the above genotypes she could produce an egg cell A- or o- and a baby with the phenotype (body) type A blood, Rh negative.

To set up the punnett squares:

dad AA+- with mom AA+-  (dad always goes on top of punnett suare)

A+     A-

A+

A-

you get a 1 in 4 chance of a AA-- (type A negative baby)

A+     A-     o+     o-

A+

A-

you also get a 2 in 8 (1in4) chance of a type A negative child

A+     A-     o+     o-

A+

A-

o+

o-

you get a 3 of 16 chance of a type A negative child

(Even a type AB+- father or mother could produce sperm and egg cells capable of making a Type A negative child.)

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Yes, this is possible.  Don't forget each parent has a dominant gene and a recessive gene.  If both of the parents carry a recessive gene in their blood for A- then it is possible for them to have a child with A+.  I am a fraternal twin and my sister is B+ and I am B-.  Draw a Punnett Square using a capital A for dominant and lower case a for recessive then cross reference the parents and you can determine the percentage for a group of parents to have an A- child.

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Both parent have a recessive - gene.

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Yes it is possible, both parent must have a recessive - gene, therefore giving their child a 25% possibility of having a -