One group study shows females have low RBC count compared to males of same age group. It is due to?

Menstrual blood loss plays a major role in iron metabolism. The average monthly menstrual blood loss is approximately 50 mL. Women with heavy menstrual losses must absorb 3-4 mg of iron from the diet each day. Women with menorrhagia of this degree will almost always have low RBC count. Testosterone stimulates erythropoiesis which accounts for the high RBC count and haemoglobin content in male. RBC count in males: 4.5-6 million/microL and that of females: 4-5.5 million/ microL Ref: Strecker-McGraw M. (2011). Chapter 41. Hematologic Emergencies. In R.L. Humphries, C. Stone (Eds), CURRENT Diagnosis & Treatment Emergency Medicine, 7e.