• Estradiol is the most abundant and active female hormone. It plays a major role in being a female, order of menstrual cycle, maintenance of bone density, prevention of cardiovascular disease, and feminine aggression. A postmenopausal level is not considered to be acceptable for most women's optimal health.
• Estradiol's presence may play a major role in the development of prostatic cancer. Therefore, it is essential to measure its level especially in men over 40 years of age. If there is too much of it in the blood, it not only could contribute to the development of prostate cancer but it will also contribute to demasculanization and a diminished libido.
• 17beta-estradiol (E2) is essential for initiating the growth of prostate cancer. It was found that a 50 years old man may have more estradiol in his blood than a same age woman.

Values obtained with different assay methods should not be used interchangeably.