Q: Is it physiologically possible for a baby to have a different blood type from his parents (dad is B+, mom is O+ and baby is A+)?
A: In the classic genetics of inheritance, the answer is no. Although there may be rare genetic mutations that can make this possible, if mom is O+ and baby is A+ then the dad usually has to be AB+, A+, AB-, A-. Please don't take this as 100% truth. As I said, rare genetic mutations can make this happen. If there are any questions about paternity, please consult a geneticist to be 100% sure.