WHAT DOES THAT EVEN MEAN?
It simply means know your Genotype. "Genotype is the genetic makeup of an organism and it results in some of the physical characteristics of that organism. Genotype is an inherited trait and hereditary information passed by the parents determines the genotype. The entire genetic information about an organism is contained in a genotype – even those characteristics which are not expressed visually."
The genotypes in humans are AA, AS, AC, SS.
Genotypes are not to be confused with blood types/groups. Blood types are based on the presence or absence of specific antigens on red blood cells.
These are the four main categories into which human blood are divided: A, B, AB, and O.
Now, go out there and do the simple blood test to know your genotype if you do not know it.