There are different blood types: A, B, AB, and O, with each also being Rh-positive or Rh-negative. Knowing your blood type is important for safe blood transfusions and organ transplants. Type ...

Close up photo of female scientist holding a laboratory pipette and a blood sample tube for covid-19 in laboratory. She is wearing a protective suit, laboratory glasses, surgical mask and surgical ...

A person's blood type is determined by "the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body," according to American Red Cross.

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.