Puberty and adolescence

Through puberty and adolescence, girls become women and boys become men. Puberty sees the start of the physical aspects of this transformation and occupies roughly the first half of the teenage years. Adolescence covers the second half of tne teenage period up to the usually undefined point at which a person is seen to be “adult.” It is a time of learning independence and emotional maturity and of coming to terms with adulthood.

It can be a difficult time for the teenager because of mood changes, the strength of sexual feelings, and the desire or even the need for ever-increasing independence.

Physical development in boys and girls is controlled by hormones released from the anterior pituitary, which is stimulated by a releasing factor (black arrow) from the hypothalamus in the brain. In boys, pituitary hormones make the testes produce testosterone, which causes the body to develop such male characteristics as facial and body hair, male sexual organs, a deeper voice, and heavier musculature. In girls, pituitary hormones stimulate the production of progesterone and estrogen by the ovaries. Progesterone initiates the development of the breasts and affects the menstrual cycle; estrogen causes the body to develop female sexual characteristics. In both boys and girls, the levels of sex hormones in the blood are monitored by the hypothalamus: this feedback mechanism controls the hormone output of the pituitary.

Physical changes in girls

The physical changes of puberty usually occur in girls between the ages of 10 and 14, although there is considerable individual variation. Nutrition, heredity, body weight, and social factors all influence the age at which any particular girl begins puberty. The changes are started by hormones released from the pituitary gland at the base of the brain; these hormones cause the ovaries to mature and to release estrogen into the bloodstream. Estrogen causes the nipples to darken and the breasts to grow, slowly at first, as the milk ducts enlarge and increase in number. Pubic hair, followed by axillary (armpit) hair, begins to appear, then gradually grows coarser, darker, and more prolific.

About a year after these changes begin, the menstrual periods start, when the uterus sheds its lining each month. The menarche (first period) is usually preceded by a monthly clear discharge for one or two months. The first periods may be very light, not much more than a slight, bloodstained discharge, or may start immediately with a normal adult level of menstrual flow.
The estrogen causing the external changes of puberty also induces growth of the uterus, vagina, ovaries, and labia (the folds of skin around the entrance to the vagina), and changes the vaginal secretions from alkaline to acid. The pelvis grows wider to allow for childbearing, and other hormones (androgens) in the bloodstream cause a slight hair growth on the upper lip.
Ovulation (production of an egg for possible fertilization) usually starts a few months after the first menstrual period.

Physical changes in boys

Changes in boys at puberty are also started by pituitary hormones, which cause the testes to grow and the scrotum to enlarge and become ridged and darker in color. Spermatozoa begin to be formed, although many of these do not reach maturity in the early years. Testosterone released into the bloodstream causes a sudden increase in height and weight. The penis increases in size, and hair begins to appear in the armpits and in the pubic region. In early puberty, boys may also experience uncomfortable swelling in one or both breasts. This is caused by sensitivity to hormones in the blood, and soon disappears.

The hormones that bring about a boy’s gradual physical and emotional development into a man have various direct and indirect effects on the body. The vocal cords enlarge as changes occur in the larynx, and the voice slowly deepens. The prostate gland starts to secrete substances that form part of the seminal fluid. Hair begins to grow in the pubic region and on the face. The muscles grow, the shoulders broaden, and the body thickens generally. Boys usually complete these physical changes by about age 18.

Changes in both sexes

At puberty, both boys and girls tend to accumulate extra fat. It disappears later in most boys, but girls tend to retain it around the hips, thighs, and breasts. Because of increased hormonal action, the sebaceous glands increase their activity, causing the skin to become oilier and coarser. Blood pressure and lung capacity increase, but average heart rate, respiration (breathing) rate, and body temperature all tend to fall as the child gets older. The muscles become stronger and, particularly in boys, more noticeable. Sexual urges grow stronger as hormonal action increases and the sex organs develop.


When axillary (armpit) and pubic hair starts to grow, perspiration also increases in those areas, and teenagers become conscious of the need to pay extra attention to personal hygiene. When their periods start, girls should be advised how sanitary napkins or tampons are used and how often they should be changed. The overactive sebaceous glands in the skin, which are frequently the cause of teenage skin problems (notably acne), can be controlled by careful washing and specially medicated soaps and creams.

Social and psychological development

The psychological changes involved in puberty and adolescence are immense, as teenagers face adulthood, gain independence, and come to terms with their maturing bodies and sexual feelings. Teenagers need great understanding from their parents, teachers, and other concerned adults during puberty but providing this can be difficult, because teenagers can be very unlovable when they are confused by mental, physical, and emotional changes beyond their control.

Most teenagers become interested in sexual relationships. These may be very casual, as emotional attachments move easily among several different boyfriends or girlfriends, or they may be far more profound. Romantic love is a common feature of the teenage years, and many relationships formed at this time are taken very seriously.

Mood changes

Adolescence can be a worrying time because hormonal activity often induces sudden and inexplicable mood changes, which may surprise the teenager as much as the family. The teenager does not really know whether he or she is a child or an adult. An adolescent is expected to obey parental and school discipline, and yet is also expected to be self-motivated about work, looking after money and other responsibilities. Most teenagers also worry that they are developing too fast or too slowly, or that they are not changing in the same way as everyone else. Any negative feelings about puberty that have been acquired in childhood come to the forefront during the teenage years.

Adolescent girls may suffer additional problems due to menstruation, specifically premenstrual tension and menstrual cramps. Premenstrual tension is a mixture of physical and psychological symptoms that may include fluid retention, temporary weight gain, skin disturbances, headaches, depression, fits of temper, breast tenderness, and afeeling of heaviness and lethargy. The premenstrual syndrome occurs for several days before, and during the first few days of, each period, and can be aggravated by stress. Menstrual cramps also may begin in adolescence and may sometimes be severe enough to cause temporary absence from school. These problems can upset a girl’s life considerably and cause substantial distress.


Sexual feelings emerge slowly during puberty and become a dominating influence during adolescence. Curiosity about sexual matters and the physical characteristics of the opposite sex is intense for most adolescents. This curiosity may take the form of questions to parents or teachers, but is also pursued by reading as much as possible relating to sexuality and by sharing information with other children of the same age group. Sexuality has a social as well as a physical aspect, and many young teenagers feel happier meeting the opposite sex in groups, or at least with another couple, before they are confident enough to go out with their date alone.

Social and psychological problems

For most people the changes of adolescence are temporary troubles. For some, however, they can cause serious problems. Compulsive eating, leading to excessive weight gain, or self-starvation, called anorexia nervosa, may occur. Periodic depression as an aspect of mood changes is common, but can become acute and, in extreme cases, result in attempted or actual suicide.
Social problems tend to be associated with an adolescent’s desires for sexual discovery, novelty, excitement, independence, and rebellion. They are most likely to occur when circumstances or an individual’s reaction to them get out of control. The main areas of teenage social problems in Westernized societies are concerned with sex (in particular with sexual diseases or unwanted pregnancies), drug abuse, and crime.

An awareness of the causes of sexual problems and the willingness of parents to advise helpfully about their avoidance or, if necessary, their treatment, is the easiest solution to the first of these problem areas. Professional advice and treatment centers such as Family Planning or contraception clinics, pregnancy advisory centers, and clinics for the diagnosis and treatment of sexually transmitted (venereal) diseases are alternatives or adjuncts to parental guidance.
Criminal activities, such as drug abuse or petty theft, are often tempting to teenagers because of the excitement of risk and the gesture of rebellion they embody. But minor “risk-taking” leads all too easily usually through association with friends who take similar or greater risks to deeper involvement. The penalties are also serious because they don’t stop when the “debt to society,” whether a fine or a prison sentence, has been paid. A criminal conviction can, and usually does, literally change a person’s life.

Such difficulties affect only a minority of teenagers, however, and most families cope with the emotional upsets of adolescence with a minimum of antagonism. Even where conflict occurs it tends to pass quickly because it is more likely to be an expression of reaction to change by either parents or children than a reflection of deeper hostility.

The growth of boys and girls follows similar but not identical patterns from birth to the late teens, when height and weight stabilize. The graphs show the increase in height and weight for each sex. The average height and weight of each sex (the dark mid-lines of each graph) remain almost identical until the mid- to late-teens, when young men continue to grow after young women stop. Differences occur chiefly in rates of growth—with girls growing faster in the early teens—and in variations between maximum and minimum heights and weights, with girls showing a greater variation in weight.


As they begin to develop into adults and seek their own standards, teenagers naturally tend to become resentful of rules and restrictions imposed by others. School and family discipline is irksome, and rebellion against authority is a common reaction. Parental values are superseded by influences from school, the media and, in particular, the opinions of friends. Many adolescents become strongly concerned about moral questions, especially those relating to social issues such as justice, politics, religion, war, and class. As a result, they frequently come into conflict with their families, especially over specific principles or details of ideology.

Most adolescents live at home during this transitional period, while they are finishing their schooling or while training for a job. Meanwhile, they become old enough to drink, smoke, vote, drive, and marry, and crave emotional and financial independence. This wrestling with two different roles as an independent individual on the one hand and as part of a family on the other has a maturing effect that probably does as much as anything else to equip the adolescent for adulthood.