According to the American Red Cross, the most common blood type is O positive, which is the blood type for 37% of the ...

Not everyone on Earth has the same blood type. Researchers are still trying to figure out why there are so many, but these different blood types can have deadly downsides. The surface of our red ...

In the past, this typically involved identifying specific phenotypes (in particular, specific blood types) in the child and using this information to either "rule in" or "rule out" possible fathers.