Can an o positive blood type and an o negative make an ab positive baby?
No, it would be impossible for two Type O blood parents [regardless of their Rh factor] to have a Type AB baby. I’ll try to explain why. Blood type is determined at the moment of conception by a combination of two genes: one gene that comes from the biologic mother and another gene that comes from the biologic father. The gene for blood type O is recessive, and the genes for types A and B are dominant. A person with type O blood has two genes for type O blood [recessive], and that’s the gene he/she will pass on to each and every one of his/her offspring. A couple in which BOTH partners have type O blood will necessarily produce type O blood offspring exclusively. If a child with other blood type {type A or type B} is born to such a couple, it means that the man isn’t this child’s biological father, because neither he nor his wife has another kind of gene but type O to pass on to their offspring. A person with type AB blood has received one type A gene AND one type B gene {both of them
