Testosterone, a hormone classed as an androgen, is made in the testicles of the male and in the ovaries of the female. It is responsible for developing and maintaining male and female characteristics. Made from cholesterol, this steroid is most prevalent in utero, immediately after birth, at puberty and during adulthood. According to Texas State University, testosterone influences physical and psychological aspects of males and females.
Physical
According to an entry authored by P.H. Mehta and colleagues in the "Encyclopedia of Social Psychology," testosterone increases during puberty and is responsible for a young teen's deepening voice and body hair, and in males, the growth of facial hair. The hormone gives boys masculine facial characteristics and body definition as the muscles develop. It also affects bone and brain development and energy levels in both sexes. Females have one seventh the amount of testosterone as males.
Psychological
Testosterone influences behavior. The University of Texas notes that aggressive and competitive tendencies are related to testosterone. Studies indicate that young males' testosterone levels tend to increase with winning and decrease with losing. Young females with higher levels of testosterone may be more dominating, may smile less and may be more stereotyped.
Sexual
The University of Michigan Health System states that testosterone in both males and females affect sexual functioning and genital tissue development. The distribution of fat that gives a girl the curves of a woman is influenced by testosterone. Testosterone is also responsible for sexual desire in both sexes.
