Rh Factor Inheritance Calculator

The Rh factor is a protein on red blood cells that you either inherit (+) or don't (−) — and knowing the odds matters for pregnancy planning and medical care. The Rh Factor Inheritance Calculator uses both parents' blood types to estimate the genetic probability a child will be Rh positive or Rh negative. Select the Mother's Blood Type and Father's Blood Type to see the Rh Positive Probability and Rh Negative Probability for their child.

Results

Rh Positive Probability

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Rh Negative Probability

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Results Table

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Frequently Asked Questions

How is Rh factor inherited from parents to child?

Rh factor is inherited through genes. If both parents are Rh+, the child has a 75% chance of being Rh+ and 25% chance of being Rh-. If one parent is Rh+ and the other is Rh-, there's a 50-50 chance. If both parents are Rh-, the child will be 100% Rh-.

Can a child have a different Rh factor than both parents?

Yes, if both parents are Rh+ but carry a recessive Rh- gene, their child can be Rh-. This happens in about 25% of cases when both parents are heterozygous Rh+.

What happens if mother is Rh- and baby is Rh+?

This can cause Rh incompatibility, where the mother's immune system may attack the baby's red blood cells. This is prevented through Rh immunoglobulin injections during pregnancy and after delivery.

Is Rh negative or positive more common?

Rh positive is much more common, found in about 85% of the population. Only about 15% of people are Rh negative, making it the minority blood type.

Can two Rh+ parents have an Rh- child?

Yes, if both Rh+ parents carry the recessive Rh- gene. In this case, there's a 25% chance their child will be Rh negative, inheriting the recessive gene from both parents.

Does Rh factor affect blood type compatibility?

Yes, Rh factor is crucial for blood transfusions and organ transplants. Rh- individuals can only receive Rh- blood, while Rh+ individuals can receive both Rh+ and Rh- blood.

How accurate is genetic inheritance prediction?

Genetic inheritance follows Mendelian principles and is highly predictable for Rh factor. However, this calculator provides probability estimates based on typical inheritance patterns - actual results may vary due to rare genetic variations.