If both the parents have blood group B+, can the child have A+?

If both parents have blood group B+, it is not possible for their child to have blood group A+. Here's why:

1. ABO Blood Type Inheritance: The ABO blood type is determined by a single gene with three alleles: A, B, and O. The A and B alleles are codominant, meaning that if an individual inherits both, they will have AB blood type. The O allele is recessive, meaning it will only result in O blood type if an individual inherits two O alleles. Since both parents are B+, they can only pass on B or O alleles to their children, not A alleles12.

2. Possible Blood Types for B+ Parents: Two B+ parents can have children with either B or O blood types. This is because each parent can be either BB or BO genotype. If both are BO, they can pass on the O allele to their child, resulting in an O blood type. However, they cannot pass on an A allele, so the child cannot have A+ blood type12.

3. Rh Factor Inheritance: The Rh factor is inherited separately from the ABO blood type. Since both parents are Rh+, their child will also be Rh+, regardless of whether they have B or O blood type45.

In summary, if both parents have B+ blood type, their child can have B+ or O+ blood type but not A+ blood type.