We each have a blood type determined by a chemical marker, called an antigen, that forms on our red blood cells. But some of us, for genetic reasons, actually have those blood type antigens circulating through our bodies, and we secrete them through our skin and in all of our bodily fluids. About 80% of us are these so called "secretors", and if you're one of them, that means that mosquitoes can not only smell your blood from far away, they can actually tell what type you are. Research has repeatedly shown that mosquitoes bite secretors more often than non-secretors, and for some reason, they also prefer people with the "O" blood type, like me. If that isn't discriminatory, I don't know what is.