Why Do Males Have A Higher Red Blood Cell Count Than Females?

There maybe 2 reasons...
1-females have oestrogen...which suppresses action of erythropoietin-a hormone required for erythropoiesis..so females have lower blood count

2-testosterone present in males has an accelerating effect on erythropoietin...so males have slightly higher rbc count..

RBC's transport oxygen around the body. Men have evolved a greater RBC count than women over time due to increased oxygen requirement during activities such as hunting. There is also a positive correlation between RBC count and muscle mass.

Because females have periods