Anemia is a condition in which a person has low red blood cells as measured by “hemoglobin” and “hematocrit.” Hemoglobin is the oxygen carrying protein within red blood cells and hematocrit is the percentage of red blood cells in a sample of blood take from a patient (red blood cells, white blood cells, proteins and plasma). Women have a lower baseline hemoglobin and hematocrit than men to begin with. Normal values are 12-16 g/dL hemoglobin and 36-48% hematocrit for women and 14-18 g/dL hemoglobin and 40-54% hematocrit for men. In addition to women having a lower baseline amount of red blood cells than men, they also have menstrual bleeding every month which serves to decrease their hemoglobin and hematocrit even more. Therefore, women are more likely than men to become anemic but supplementation with iron is able to correct anemia in most cases of this physiologic anemia.