Parents Blood Type and Child: A, B and AB Chart

If you have ever wondered about the parents blood type and child connection, you are in good company. People ask whether two A positive parents can have an O baby, what happens with A and B parents, and whether two Rh positive parents can have a negative baby. This guide answers all of those questions with a clear chart and short explanations.

It pairs well with our guide to O positive parents, and with the basics of what makes a good parent.

How Blood Type Is Inherited

Each person has two ABO genes, one from each parent. A and B are dominant and O is recessive. That is why a parent with group A can carry a hidden O gene, and why two A parents can have an O child. The Rh factor works separately: positive is dominant and negative is recessive.

1. Group A is either AA or AO. Group B is either BB or BO.
2. Group AB is always A and B together.
3. Group O is always OO.
4. A child gets exactly one gene from each parent, chosen by chance.

Chart: A, B and AB Parents and Their Children

Use this table to look up the possible blood groups of a child. It covers combinations people commonly search for, such as a positive and b positive parents and ab positive blood type parents.

Parents	Possible ABO types	Possible Rh
A+ and A+	A or O	Positive (negative only if both parents carry the negative gene)
A+ and A−	A or O	Positive or negative
A+ and B+	A, B, AB or O	Positive (negative only if both parents carry the negative gene)
A+ and B−	A, B, AB or O	Positive or negative
A+ and AB+	A, B or AB	Positive (negative only if both parents carry the negative gene)
A+ and AB−	A, B or AB	Positive or negative
A− and A−	A or O	Negative only
A− and B+	A, B, AB or O	Positive or negative
A− and B−	A, B, AB or O	Negative only
A− and AB+	A, B or AB	Positive or negative
A− and AB−	A, B or AB	Negative only
B+ and B+	B or O	Positive (negative only if both parents carry the negative gene)
B+ and B−	B or O	Positive or negative
B+ and AB+	A, B or AB	Positive (negative only if both parents carry the negative gene)
B+ and AB−	A, B or AB	Positive or negative
B− and B−	B or O	Negative only
B− and AB+	A, B or AB	Positive or negative
B− and AB−	A, B or AB	Negative only
AB+ and AB+	A, B or AB	Positive (negative only if both parents carry the negative gene)
AB+ and AB−	A, B or AB	Positive or negative
AB− and AB−	A, B or AB	Negative only

If Both Parents Are A Positive

1. ABO: the child can be A or O. Group O is possible when both parents carry a hidden O gene.
2. Rh: the child can be positive, or negative if both parents carry the hidden negative gene.
3. A child of two A positive parents cannot be B or AB.

If Both Parents Are B Positive

1. ABO: the child can be B or O.
2. Rh: usually positive, but negative is possible if both carry the hidden gene.
3. A child of two B positive parents cannot be A or AB.

A Positive and B Positive Parents

This pairing gives the widest range. The child can be A, B, AB or O. If the A parent carries a hidden O gene and the B parent does as well, an O child is possible. With the Rh factor, positive is most likely, and negative is possible if both carry the hidden negative gene. The same applies to a positive and b negative parents, b positive and a negative parents and a negative and b positive parents, except that when one parent is negative, a negative child is possible only if the positive parent carries a hidden negative gene.

A Positive and A Negative Parents

The child can be A or O. For Rh, the child may be positive or negative. A negative child is possible only if the positive parent carries a hidden negative gene.

AB Positive Blood Type Parents

1. AB and AB: the child can be A, B or AB. Group O is not possible.
2. AB and A: the child can be A, B or AB.
3. AB and B: the child can be A, B or AB.
4. AB and O: the child can only be A or B. See our O positive parents chart.

Can Two Rh Positive Parents Have a Negative Baby?

Yes. This is one of the most common questions, and the answer is simple. A person who is Rh positive may carry one positive and one negative gene. If both parents have this mix and each passes on the negative gene, the baby will be Rh negative. It is a normal result of inheritance and no cause for worry. If one parent is Rh negative and the other positive, a negative child is also possible.

Doctors do pay attention to Rh when a mother is negative and a baby may be positive, so antenatal care normally includes a simple blood test. If you are expecting, a doctor or lab can confirm your type and advise you.

Worked Examples

1. Mother A positive, father B positive: children may be A, B, AB or O. Four siblings could each have a different ABO group.
2. Mother AB positive, father A negative: children may be A, B or AB, and positive or negative.
3. Mother B negative, father B positive: children may be B or O. For Rh, positive or negative are both possible.
4. Mother A negative, father A negative: children may be A or O, and all will be Rh negative.

Rh Factor Made Simple

The Rh factor is a protein on red blood cells. If you have it, you are positive, and if you do not, you are negative. Positive is dominant, which means one positive gene is enough to make you positive. Negative shows only when both genes are negative. That is why two positive parents can have a negative child, but two negative parents can only have negative children.

1. Positive and positive: child is positive, or negative if both carry the hidden gene.
2. Positive and negative: child can be positive or negative.
3. Negative and negative: child is always negative.

Why Siblings Can Have Different Blood Types

Each child receives a fresh, random pick of one gene from each parent. That is why brothers and sisters can have different blood groups even though they share the same mother and father. One child may receive the hidden O gene from both sides and be group O, while another receives A from one parent and B from the other and is group AB. This is normal, healthy and expected, and it is one more reason why a blood group should never be used to question a family.

It also explains why a grandparent’s blood type can “skip” a generation. A hidden gene can travel quietly through a parent and appear again in a grandchild.

Useful Habits for Families

Knowing each family member’s type is a sensible piece of health knowledge, especially for expectant mothers and for emergencies. A few simple habits help.

1. Ask your doctor for a lab-confirmed blood type for every family member.
2. Store the results with other health documents, where both husband and wife can find them.
3. Explain blood type to older children as a simple science lesson, never as a family secret or a test.
4. Never guess a child’s type from a chart. A short lab test gives the real answer.

A Kind Reminder About Using This Chart

This chart explains general inheritance. It is not a parentage test, and it cannot decide who is a child’s mother or father. Please never use it to doubt your spouse or to cause suspicion in a family. Many unusual-looking results are explained by hidden genes or by a mistake in recording a type.

A home is held together by trust, respect and good character, not by a blood chart. For anything medical, a doctor or lab can confirm the facts.

Common Mistakes to Avoid

1. Treating the chart as a test of loyalty or parentage.
2. Ignoring hidden genes. A and B parents can carry O.
3. Mixing up Rh with ABO. They are inherited separately.
4. Relying on memory for your own type. Ask a doctor or check your lab report.

Frequently Asked Questions

If both parents are A positive, what is the child?

The child can be A or O, and positive or negative.

If both parents are B positive, what is the child?

The child can be B or O, and positive or negative.

Can two Rh positive parents have a negative baby?

Yes, if both carry a hidden negative gene and each passes it on.

Can A and B parents have an O child?

Yes, if each parent carries a hidden O gene. Their child can also be A, B or AB.

For more family guidance, visit our Family and Parenting section, or read the rules good parents follow.