Q: What
are hormones? A: Although
there are a variety of hormones pumping through the veins of males and females
at any given time, let’s keep it simple and focus on the major classifications
of the hormones involved in sexual differentiation: Androgens and
estrogens. Androgens is the generic term for the
hormones that promote the development and functioning of the male reproductive
system. Estrogens is the generic term for the
hormones that stimulate functioning and maturation of the female reproductive
system. Both classes of female and
male hormones are present in the bodies of males and females, but in
drastically different amounts.
The primary “male” hormone is
testosterone. Most men produce 6-8 milligrams of testosterone (an androgen)
each and every day, compared to the typical woman who produces about 0.5
milligrams daily. Females
hormones, also known as estrogens, are also present in both sexes, but of
course, in larger amounts for women.
Estrogens are the sex hormones that
are produced mainly by a female’s ovaries that stimulate the maturation of
secondary sex characteristics.
Secondary sex characteristics include the growth of a female’s
reproductive organs, as well as her breasts and pubic hair. Estrogens also regulate the functioning
of a female’s menstrual cycle.
Estrogens do not play a significant
role in a female’s level of sexual desire, however, they are important in
maintaining the health of the vaginal lining and elasticity, producing vaginal
lubrication, and in preserving the texture and function of a woman’s breasts
(i.e., lactation during and after pregnancy).
Estrogens have no known function in
men. However, an unusually high level of estrogen in men may reduce sexual
desire, create erectile difficulties, may produce some breast enlargement, and
can result in the loss of body hair in some men. Androgens are sex hormones primarily produced by a male’s
testes, but are also produced in the adrenal gland of both sexes, as well as in
small amounts by the female’s ovaries. Androgens (like testosterone) help
to initiate the development of the testes and penis in the male fetus. They trigger the start of puberty and
influence muscle development, the growth of facial, body and pubic hair, and
cause a male’s voice to deepen.
Together, all of these pubertal changes taking place in a male’s body
are called secondary sex characteristics. Research has also provided evidence
that pre-natal hormonal exposure influences brain development; creating some of
cognitive differences among males and females, as well as being instrumental in
the biological foundations of sexual orientation.
During and after puberty,
androgens, specifically testosterone, play a significant role in the regulation
of an individual’s sex drive. Large deficiencies of testosterone may cause a
drop in sexual desire, and excessive testosterone levels may heighten sexual
desire in both males and females.
However, testosterone levels within the normal range have little effect
on either sex’s sexual interest.
An individual’s sex drive is much more likely to be influenced by
psychological and emotional factors, as well as external stimuli (i.e., sights,
sounds, smells, and touch).
One last hormone-fact regarding
testosterone in men deserves to be mentioned. Research has found a link between high levels of
testosterone and balding in men.
Men with high levels of testosterone also produce large amounts of
cortisol. Cortisol is a steroid (aka androgen) hormone that is released in men
due to high stress levels, which in turn, has been linked to testosterone
levels. Cortisol inhibits follicle
growth by continually weakening the root cells of hair follicles on a man’s
head. Since higher levels of
testosterone in men is also related to greater athletic ability, stamina and
sexual desire, it is not surprising that male-pattern balding is so prevalent
throughout the world. Men with a
lot of testosterone often do not find it difficult finding mates.
References
Joannides, P., & Gross, D. (2009). Guide to Getting
it On: For Adults of All Ages (6
ed.). Saline, MI: McNaughton &
Gunn.
Poor, V., Juricskay, S., & Telegdy, E. (2002). Urinary steroids in men with
male-pattern
alopecia. Journal of Biochemical & Biophysical Methods, 53(1-3), 123-131.
Savin-Williams, R., & Diamond, L. M. (1997). Sexual orientation as a developmental context for lesbians, gays, and bisexuals: Biological perspectives. In Uniting psychology and biology: Integrative
perspectives on human development. Segal, Nancy L.,
Weisfeld, G. E., & Weisfeld, C. C. (Eds.); pp. 217-238. Washington, DC,
USA: American Psychological Association.
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