Puberty is the period of human development during which physical growth and sexual maturity occurs.
Description
The word puberty is derived from the Latin pubertas, which means adulthood. Puberty is initiated by hormonal changes triggered by a part of the brain called the hypothalamus, which stimulates the pituitary gland, which in turn activates other glands as well. These changes begin about a year before any of their results are visible. Both the male reproductive hormone testosterone and female hormone estrogen are present in children of both sexes. However, their balance changes at puberty, with girls producing relatively more estrogen and boys producing more testosterone.
Beginning as early as age eight in girls—and two years later, on average, in boys—the hypothalamus signals hormonal change that stimulates the pituitary. In turn, the pituitary releases its own hormones called gonadotrophins that stimulate the gonads and adrenals. From these glands come a flood of sex hormones—androgen and testosterone in the male, estrogen and progestin in the female—that regulate the growth and function of the sex organs. It is interesting to note that the gonadotrophins are the same for males and females, but the sex hormones they induce are different.
The experience of puberty is new and unusual for both boys and girls. It is not something that happens overnight, but rather it is a process that occurs in stages and at different ages for different people. It is perfectly normal, for example, for one person to have already started developing while one's best friend of the same age has not. The age at which puberty begins can vary widely between individuals. Timing of onset is affected by genetic factors, body mass, nutritional state, and general health.
School age
The average age for first signs of breast development in girls is about 10.5 years, with menstruation and fertility following about two years later. Average age for first signs of testicle enlargement in boys is 11.5 years. Puberty may not begin until age 16 in boys and continue in a random fashion beyond age 20. In contrast to puberty, adolescence is more a social/cultural term that refers to the interval between childhood and adulthood. The duration of puberty, from time of onset to completion, varies less between children than does the age of onset. Duration of puberty in girls from onset of breast development to cessation of growth is roughly five years. Duration of puberty in boys from first testicle enlargement to cessation of growth is about six years.
Puberty has been divided into five Sexual Maturity Rating (SMR) stages by two doctors, W. Marshall and J. M. Tanner. These ratings are often referred to as Tanner Stages one through five. Staging is based on pubic hair growth, on genital development, and female breast development. Staging helps determine whether development is normal for a given age. Both sexes also grow armpit hair and develop pimples. Males develop muscle mass, a deeper voice, and facial hair. Females redistribute body fat. Along with the maturing of the sex organs, there is a pronounced growth spurt averaging three to four inches (8–10 centimeters) and culminating in full adult stature. Puberty can be early or delayed.
PUBERTY STAGES IN GIRLS
Stage One (approximately between the ages of eight and eleven): The ovaries enlarge and hormone production starts, but external development is not yet visible.
Stage Two (approximately between the ages of eight and fourteen): The first external sign of puberty is usually breast development. At first breast buds develop. The nipples will be tender and elevated. The area around the nipple (the aureole) will increase in size. The first stage of pubic hair may also be present at this time. It may be coarse and curly or fine and straight. Height and weight increase at this time. The body gets rounder and curvier.
Stage Three (approximately between the ages of nine and 15): Breast growth continues and pubic hair gets coarser and darker. During this stage, whitish discharge from the vagina may be present. For some girls, this is the time that the first menstrual period begins.
Stage Four (approximately from ages 10 to 16): Some girls notice that their aureoles get even darker and separate into a little mound rising above the rest of the breast. Pubic hair may begin to have a more adult triangular pattern of growth. If it did not happen in Stage Three, menarche (first menstruation) should start now. Ovulation may start now, too. But it will not necessarily occur on a regular basis. (It is possible to have regular periods even if ovulation does not occur every month.)
Stage Five (approximately between ages 12 and 19): This is the final stage of development. Full height is reached, and young women are ovulating regularly. Pubic hair is filled in, and the breasts are developed fully for the body.
PUBERTY STAGES IN BOYS
Stage One (approximately between ages nine and 12): No visible signs of development occur, but, internally, male hormones become a lot more active. Sometimes a growth spurt begins at this time.
Stage Two (approximately between ages nine to 15): Height increases and the shape of the body changes. Muscle tissue and fat develop at this time. The aureole, the dark skin around the nipple, darkens and increases in size. The testicles and scrotum grow, but the penis probably does not. A little bit of pubic hair begins to grow at the base of the penis.
Stage Three (approximately between ages 11 and 16): The penis starts to grow during this stage. It tends to grow in length rather than width. Pubic hair is getting darker and coarser and spreading to where the legs meet the torso. Also, boys continue to grow in height, and even their faces begin to appear more mature. The shoulders broaden, making the hips look smaller. Muscle tissue increases and the voice starts to change and deepen. Finally, facial hair begins to develop on the upper lip.
Stage Four (approximately 11 to 17): At this time, the penis starts to grow in width, too. The testicles and scrotum also continue to grow. Hair may begin to grow on the anus. The texture of the penis becomes more adult-looking. Underarm and facial hair increases as well. Skin gets oilier, and the voice continues to deepen.
Stage Five (approximately 14 to 18): Boys reach their full adult height. Pubic hair and the genitals look like an adult man's do. At this point, too, shaving is a necessity. Some young men continue to grow past this point, even into their twenties.
Common problems
When puberty occurs outside the age limits considered normal parents may be prompted to search for the cause. As health and nutrition have improved over the past few generations, there has been a gradual decrease
in the average age for the onset of puberty. These causes of early or late puberty may include the following:
Excess hormone stimulation is the cause for early puberty. It can come from the brain in the form of gonadotrophins or from the gonads and adrenals. Functioning tumors may cause overproduction of sex hormones. Brain overproduction of factors promoting sex hormone production can also be the result of brain infections or injury.
Likewise, delayed puberty is due to insufficient hormone. If the pituitary output is inadequate, so will be the output from the gonads and adrenals. By contrast, a normal pituitary overproduces if it senses there are not enough hormones in the circulation.
There are several congenital disorders called polyglandular deficiency syndromes that include failure of hormone output. Children with these syndromes do not experience normal puberty, but it may be induced by giving them hormones at the proper time.
Finally, there are in females abnormalities in hormone production that produce male characteristics, so called virilizing syndromes. Should one of these appear during adolescence, it will disturb the normal progress of puberty. Notice that virilizing requires abnormal hormones in the female, while feminizing results from absent hormones in the male. Each embryo starts out life as female. Male hormones transform it if they are present.
Delayed or early puberty requires measurement of the several hormones involved to determine which are lacking or which are in excess. There are blood tests for each one. If a tumor is suspected, imaging of the suspect
organ needs to be done with x rays, computed tomography scans (CT scans), or magnetic resonance imaging (MRI).
Puberty is a period of great stress, both physically and emotionally. The psychological changes and challenges of puberty are made infinitely greater if its timing is off.
In early puberty, the offending gland or tumor may require surgical attention, although there are several drugs as of 2004 that counteract hormone effects. If delayed, puberty can be stimulated with the correct hormones. Treatment should not be delayed because necessary bone growth is also affected.
Early puberty often begins before age eight in girls, triggering the development of breasts and hair under the arms and in the genital region. The onset of ovulation and menstruation also may occur. In boys, the condition triggers the development of a large penis and testicles, with spontaneous erections and the production of sperm. Hair grows on the face, under arms, and in the pubic area, and acne may become a problem.
Several studies indicate an increase in incidences of early puberty and other forms of early sexual development in the United States. Sexual development in children seven years of age and younger should be evaluated by a physician. In some cases, early sexual development can be caused by a tumor or other pathological conditions. Properly administered hormones can restore the normal growth pattern.
Parental concerns
Most experts suggest that parents begin short and casual discussions about the body changes that occur in puberty with their children by the age of seven or eight. Offering the child reading materials about puberty can impart information to the young person without the awkwardness that may characterize the parent-child conversations. Parents can then offer their children opportunities to ask questions or to discuss any aspects of puberty and sexuality that may arise from their reading.
It is also a good idea for parents to talk to their children about proper hygiene at the onset and during puberty. While good hygiene is important for everyone at any age, it can require greater care at the onset of puberty. Hormones produced by the maturing body bring about physical changes that require greater attention when it comes to hygiene. For a young girl or boy, this means taking more time to clean the body, especially the sexual organs, to treat acne, use mouthwash for bad breath, and deodorant for stronger body odor.
When a boy or girl begins to go through puberty, the body produces more perspiration because sweat glands, some of which are located near the underarms, become more active. More perspiration means a different type of body odor, one that is stronger and similar to an adult's. Daily bathing and showering are enough to control body odor, along with deodorants and antiperspirants.
Boys should be instructed to wash their genitals every day. This includes washing the penis, the scrotum that holds the testicles, the anus, and pubic hair with water and mild soap. Uncircumcised boys need to be instructed that the foreskin should be pulled down daily to expose the tip of the penis, which should then be washed with mild soap and water.
In girls, it is perfectly natural to have a slight sweet smell from the vagina that is inoffensive. A strong, foul odor indicates a possible infection. With treatment, the infection goes away and so does the strong odor. Vaginal discharge is a necessary part of the body's regular functioning. Normal discharge, usually clear to white, is part of the body's self-cleaning process. As discharge leaves the body, it takes bacteria with it, which helps prevent vaginal infections. Parents should stress that girls clean the vaginal area with a mild soap and water
Puberty
Boys
Girls
SOURCE:Child Development Institute. http://www.childdevelopmentinfo.com. 2005.
on a regular basis to help control bacteria growth and limit infections.
When to call the doctor
Parents should consult a pediatrician or physician when their child shows signs of either early or delayed puberty.
KEY TERMS
Adrenal gland—A small gland located above the kidney (one on each side) that secretes various hormones.
Circumcision—A surgical procedure, usually with religious or cultural significance, where the prepuce or skin covering the tip of the penis on a boy, or the clitoris on a girl, is cut away.
Estrogen—Female hormone produced mainly by the ovaries and released by the follicles as they mature. Responsible for female sexual characteristics, estrogen stimulates and triggers a response from at least 300 tissues. After menopause, the production of the hormone gradually stops.
Estrus—A regular period of sexual excitement in females.
Gonadotrophin—Hormones that stimulate the ovary and testicles.
Gonads—Organs that produce gametes (eggs or sperm), i.e., the ovaries and testes.
Hypothalamus—A part of the forebrain that controls heartbeat, body temperature, thirst, hunger, body temperature and pressure, blood sugar levels, and other functions.
Menstruation—The periodic discharge from the vagina of blood and tissues from a nonpregnant uterus.
Pituitary gland—The most important of the endocrine glands (glands that release hormones directly into the bloodstream), the pituitary is located at the base of the brain. Sometimes referred to as the "master gland," it regulates and controls the activities of other endocrine glands and many body processes including growth and reproductive function. Also called the hypophysis.
Testosterone—Male hormone produced by the testes and (in small amounts) in the ovaries. Testosterone is responsible for some masculine secondary sex characteristics such as growth of body hair and deepening voice. It also is sometimes given as part of hormone replacement therapy to women whose ovaries have been removed.
Virilizing syndromes—Abnormalities in female hormone production that produce male characteristics.
BOOKS
Bailey, Jacqui, and Jan McCafferty. Sex, Puberty, and All that Stuff. Hauppauge, NY: Barrons Educational Series, 2004.
Madaras, Lynda, et al.What's Happening to My Body? Book for Boys. New York: Newmarket Press, 2000.
——. What's Happening to My Body? Book for Girls. New York: Newmarket Press, 2000.
McCave, Marta. Puberty's Wild Ride. Philadelphia: Family Planning Council, 2004.
PERIODICALS
Brunk, Doug, "Navigating Tx [Treatment] of Boys on the Brink of Puberty." Pediatric News (October 2001): 31.
Herman-Giddens, Marcia E., et al. "Navigating the Recent Articles on Girls' Puberty in Pediatrics: What Do We Know and Where Do We Go from Here?" Pediatrics (April 2004): 911–17.
"New Study Identifies Gene Signaling Puberty." Genomics & Genetics Weekly (November 14, 2003): 33.
Ramsayer, K. "Pesticide May Hinder Development in Boys." Science News (December 13, 2003): 372–73.
Wang, Youfa. "Is Obesity Associated with Early Sexual Maturation? A Comparison of the Association in American Boys Versus Girls." Pediatrics (November 2002): 903–10.
Wellbery, Caroline. "Cut-Off Age for Precocious Puberty Is Too Young." American Family Physician (May 1, 2003): 2001.
ORGANIZATIONS
American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007. Web site: <www.aao.org>.
Precocious Puberty Support Network. c/o MAGIC Foundation, 6645 W. North Ave., Oak Park, IL 60302. Web site: <www.magicfoundation.org>.
WEB SITES
"Female Puberty." Available online at <www.teenpuberty.com/index.php?section=female> (accessed October 29, 2004).
"Male Puberty." Available online at <www.teenpuberty.com/index.php?section=male> (accessed October 29, 2004).
"Puberty and Adolescence." National Institutes of Health. Available online at <www.nlm.nih.gov/medlineplus/ency/article/001950.htm> (accessed October 29, 2004).
