It's a hormone present in both male and female.
Testosterone allows men to grow facial hair, build strong muscles, and develop a deep voice, according to the Hormone Health Network. It also enables men to produce sperm, desire sex, and function sexually. Testosterone also may encourage men to take more risks.
Testosterone in women has many functions. It is important for bone strength and development of lean muscle mass and strength. Testosterone also contributes to overall sense of well-being and energy level. It is best known for its crucial role is a woman's sex drive or libido. More specifically, testosterone in women is responsible for the sensitivity of a woman's nipples and clitoris associated with sexual pleasure. Testosterone not only enhances the sexual mood of a woman, but the experience as well.