The real issue is not why most males have more blood than most females, which is easily answered (as others have already done) based on differences in body size. The real issue is why males have more higher blood values relative to body size than females do. read more
Although females have less blood per volume than males, it is most likely that a short fat woman like my girlfriend would have more blood in her body than a tall skinny man like me would have in his body (of course, I am not a doctor so double check with a physician!!!). read more
Males generally have larger bodies with more cells needing oxygenthan females. Also, males do not menstruate, during which femaleslose blood. read more