The Rh-Negative Recessive (Rh+/-) Trait
There are currently only 2 Rh Factor "Classifications" when related to your blood type. You are either considered to be an Rh-Positive (Rh+) or Rh-Negative (Rh-).
This is because if you have ANY Rh+ blood in your body you are called Rh+. However, in some cases an Rh+ person is born to an Rh- person. Since we each receive one blood type (the letter) and one Rh factor (+/-) from each parent; we actually have TWO.
After birth, our blood type is simplified like a mathematical equation and we end up referring to our blood type as one letter and one Rh factor. However, that portion of the full blood type that was part of the original equation does not just disappear. It will always be with you as a recessive trait.
As you can see on the illustration, when an Rh-Negative mom procreates with an Rh +/+ man, their off-spring will actually be Rh+/-, yet will be referred to as Rh+.
Two Rh+/- parents conceive a child. The each have the option of passing EITHER and Rh+ or and Rh- Factor to their child.
If they both pass down the Rh- half of themselves, the child will be Rh-/-.
If they both pass down the Rh+ half of themselves, the child will be Rh+/+.
However, if one parent passed down their Rh- half and the other parents passes down the Rh+ half; the child will be Rh+/- in true blood type.
They will be classified as Rh+ but they will always carry the recessive Rh-factor, just as the parents did.
You will notice that I often refer to these people as an Rh-Battery (Rh+/-), as it is a very simple way to visualize how the Rh-Negative Factor can be recessive in someones family and blood type. The same simplification process occurs with our actual blood type "letter" as well.