Short answer- Yes. Blood-typing and inheritance can become confusing since co-dominance occurs in the ABO groups, but not in the inheritance of the Rhesus Factor (Rh +/-)... Although Rh inheritance is more complicated (since there are more than 30 combinations possible), the possible proteins are clumped into groups of either positive (+), or negative (-). In order to be considered +, all you need is one copy, which means you could be + and - (heterozygous).
The only way for the child to be negative (-), is if both parents have a + and - copy each, and there is only a 25% chance.
Each parent gives one copy...
Mom: + - ... Dad: + - ... Therefore possible combinations are:
++ (positive) + - (positive) - + (positive) - - (NEGATIVE!)
The only way for the child to be negative (-), is if both parents have a + and - copy each, and there is only a 25% chance.
Each parent gives one copy...
Mom: + - ... Dad: + - ... Therefore possible combinations are:
++ (positive) + - (positive) - + (positive) - - (NEGATIVE!)
