A person's Rh-positive or Rh-negative blood type is determined at conception based on the Rh blood factors passed down from each parent. If a person inherits a negative factor from just one parent, they will be Rh-positive, but if they inherit a negative factor from both parents, they will be Rh-negative.

5. How did you get your Rh-Negative Blood Type? Every human being is born with two (2) individual Positive or Negative Rh Blood Factors. During conception, each parent must pass one (1) of their " Factors " on to their children. Below you can see the way a child's Positive or Negative Rh Blood Factor is finally determined; based on their receipt of the two parents combined Rh Factors. If a person has + + genes, they are Rh-positive (Rh+) If a person has + - genes, they are Rh-positive (Rh+) If a person has - - genes, they are Rh-negative (Rh-)