Baby's Blood Type. The baby will be either a+ or b+.
See below. Possibilities are as follows: a or b. The rh factor (+ or -) is more difficult to guess without further information. I suspect though that it will be +. So in review: baby will probably be a+ or b+.
A+, A=, O+, O=. Parents ab+ and o+, children could be a+, a-, o+.O-.