ok last question a male who has B+ blood how do you know what is genotype is if it is BB OR BO I want to know?

Question

if his blood type can end up creating a child with O+ blood I understand BO and O can = B+ how do we know if he has BB instead of BO? because if it's bb hes not the dad

Answer 1

It's all here

http://learn.genetics.utah.edu/units/basics/blood/types.cfm

Answer 2

You have to look at the blood types of the parents. Then, you do a punnet square and see what type he is.