Androgens such as testosterone influence the brain and behavior in two ways. First, they act prenatally and during early infancy to organize the brain. Second, circulating androgens in later adolescence and adulthood mediate behavior by altering the activity of target neural systems. Davis (2000), in fact, claims that there may be a biological link between testosterone and the modulation of sexual motivation.
Indeed, differences in testosterone levels between men and women may be partly responsible for some of the observed gender differences in sexual behavior. Higher levels of testosterone in women are associated with increased sexual desire and having a more unrestricted sociosexual orientation. Moreover, Mikach and Bailey (1999) have found that more unrestricted women report being more masculine (both as young girls and as adult women), and they are rated by observers as appearing more physically and behaviorally masculine.
Higher levels of testosterone in women also predict more frequent initiation of coitus and masturbation, more frequent intercourse during the middle of there productive cycle, greater vaginal blood flow after exposure to erotic stimuli, wearing more revealing clothing, as well as having more sexual partners.
Both human genders produce estrogen and testosterone in varying quantities and decline production as they grow older. The hormones may influence arousal through increase or decrease of erotic stimulation threshold. The actions of the hormones are central and peripheral.
Female – The sexual activity of human females do not display estrus. It is usually under little if any control of the hormones involved with ovulation. Human females show receptivity throughout the menstrual cycle, and some women report feeling interest in sex around the time of ovulation. Menopause and the surgical removal of the ovaries exert influence on a woman’s hormone levels but have little effect on her sexual interest and activity.
Men – In addition to their important organizational roles in the development of male sexual structures and characteristics, androgens activate male behavior and may influence male competitiveness, sexual frequency, and cognition.