#asktheexpert I am ab+ and my husband is a+ and my baby has ab- how come it is possible

A. It’s not typical for a baby to have a negative Rh factor (Rh-) if both parents are Rh positive, but it is possible due to the genetics of Rh factor inheritance. Here’s a simplified explanation: - **Rh Factor Inheritance**: The Rh factor is inherited separately from the ABO blood group. The Rh positive (Rh+) gene is dominant, and the Rh negative (Rh-) gene is recessive. For a child to have Rh-, they must inherit an Rh- gene from both parents. - **Possible Scenario**: If both you and your husband are Rh positive, you could still carry a recessive Rh- gene. If both of you pass the Rh- gene to your baby, the baby would be Rh negative. In your case, while both parents are Rh positive, they must carry one Rh- allele each. This allows the baby to inherit the Rh- gene from both parents, resulting in an Rh negative blood type for the baby.