The chapter delves into the multifaceted nature of estrogen beyond its role as a female sex hormone, exploring its impact on bone growth, muscle development, and overall health. It highlights the significance of estradiol in various bodily functions, from pregnancy to muscle metabolism, challenging the misconception that estrogen is exclusive to women. The conversation also discusses the differences between estrogen and testosterone in the body, touching on their effects on muscle growth, brain activity, and fetal development.