The normal levels are closer then you think. The exact numbers differ depending on what lab you ask, but the normal male range of estradiol in the blood is around 15-55 pg/mL, while the normal healthy female level can vary from 70-500 pg/mL depending on the current stage of the menstrual cycle. Normally that doesn't matter though as most of estradiol's effects are overridden by an overwhelming amount of testosterone