According to Stanford Blood Centre, there are a total of 8 types of blood groups, which are categorised based on the presence ...

Additionally, there is a protein called "the Rh factor," which can also be present (+) or absent (–). These factors help define the eight most common blood types: A positive, A negative ...

It's a bit simplistic, but you can think of the Rh factor as a protein that is either present (positive) or absent (negative) on red blood cells. Exact percentages vary with race, but most people ...

Couples are advised to know their blood types before committing to having children (Shutterstock) Couples are often plagued by various problems in marriage including fertility and pregnancy issues.