Purdue University

Cooperative Extension Service

West Lafayette, IN 47907

Living with your teenager: Understanding Physical Changes

Judith 0. Hooper

Physical Changes Are Dramatic

The years of late childhood and early adolescence contain one of the most rapid and most dramatic periods of physical change in the human life cycle. It is during these years-years that are often very difficult for both child and parents-that the child becomes an adult in physical body. It may be useful for you as the parent of a teen or teen-to-be to understand what is happening to your child. This understanding may aid you in supporting your child through this difficult time.

It may surprise you to learn that as early as age 7 or B in girls, and 9 or 10 in boys, there are the beginnings of internal changes in both the growth of organs and the presence of certain adult-type hormones. For most girls, the period of least growth is from age 9 to age 10. From about age 10 on, most girls experience a sudden growth spurt which lasts until about age 12. After 12, most girls continue growing until about age 17 or 18. Boys usually begin their growth spurt about 12 to 18 months after most girls. Boys continue to grow a good 3 to 4 years after most girls have finished growing, so that boys often do not finish growing until age 20 or 21. Of course, the average boy grows to be bigger and heavier than the average girl.

Besides growing bigger and taller, the maturing child begins to develop the bodily characteristics that distinguish the male and female adult. While it is often difficult to tell which of two t-shirt and blue jean-clad 8-year-olds is the girl and which is the boy, the differences in the same children at the age of 11 or 12 are quite obvious. For girls, the onset of menstruation is a highly important event. There is considerable evidence to show that a girl's feelings about menstruation and the way she accepts its onset has a good deal to do with her mother's feelings about it and how her mother has prepared her for it. Parents who can maintain the attitude that menstruation is an exciting developmental event, normal in all females can help their daughters experience menstruation easily.

Preparing for Change Is Important

It is now not at all uncommon for girls of 9 or 10 to begin menstruating, so it's important for parents to begin preparing their daughters for its onset at a quite early age. Girls need to know what will happen and how they will care for themselves, as well as why menstruation occurs. In addition, a girl who understands that there is no "right" age for the onset of menstruation will have far fewer worries about being "early" or "late." Finally, the menstruating girl should understand that she is now fertile and able to become pregnant.

Although boys do not experience an "event" like menstruation in girls, there are aspects of their maturing as men about which they may worry. For example, the appearance of facial and body hair may be seen as a sign of manhood, and the boy who is maturing later than his friends may have many concerns about his own masculinity. Nocturnal emissions (ejaculating while asleep), which are as normal and common as a sneeze, may be very worrying to the boy who has not been prepared for them. As with girls, the path to sexual maturity can be smoothed for boys by parents who are open and informative.

In your great-great-grandparents' time, children matured, on the average, 2 to 3 years later than they do now. In addition, it was quite common for young people to marry between the ages of 15 and 18. Today, our children are sexually mature in a physical sense long before they are capable of entering into mature, adult relationships. At the same time, however, films, television, newspapers, and other media put great emphasis on sexuality. Consequently, your teen may be very confused by the need to respond to physical impulses as seemingly encouraged by society but yet frowned upon at home, in school, and by the church or temple. Probably there is no other area in which your teen will need your support, understanding, and encouragement more than in the difficult area of making decisions about sexual activity.

Although it has been shown again and again that the best way for young people to learn about mature responsible sexuality is through their parents, many parents find it extremely difficult or impossible to discuss this subject with their children. If the parents cannot teach their children, it remains their responsibility to see that the children learn, either through providing books, through the schools or a doctor, a nurse, a social worker, or an informed adult who is willing to teach.

Physical Change Can Cause Emotional Upset

The physical growth of the child is triggered by the appearance in the body of certain hormones which stimulate the body to grow and change. It is useful for both you and your child to know and remember that these hormones are known to affect moods as well as physical growth. It is quite common for young teens to be very worried about their feelings. One girl said, "Some days I'm way up and other days I'm way down, and the way I feel doesn't seem to have much to do with what's going on around me. It really scares me that I have these feelings that come from nowhere." Once the effects of hormones on moods were explained to her, she was much less frightened of her feelings. It may be important to your child to have this information.

The sudden and extreme growth that the child goes through often can cause problems with coordination. It is not uncommon to hear a parent complain of a child who has suddenly become so clumsy that he or she "trips over the linoleum." This problem is caused partly by the general change in the body which takes getting used to, and partly by the fact that different parts of the body grow at different rates. Hands and feet, for example, grow much faster than legs and arms. Consider the problems you would have if your feet grew from their present size 6 to size 9 in the next six months Features of the face also grow at different rates, so that a young teen who is convinced that his/her nose is too big may be quite right for a time. Soon, however, the rest of his or her facial features will grow in proportion and that nose won't seem so large. Just as knowing these facts may help you to be more tolerant of your awkward child, it may also help your child be less concerned about temporary physical "problems."

Teen Health Problems Are Common

There are general health problems common among teenagers of which you as a parent will want to be aware. For example, it is extremely easy for teens to suffer from nutritional deficiencies-though this may be hard to believe if you are feeding a teen. Because of the rapid growth and changes occurring in the teen's body, there is a tremendous need for body-building foods, especially proteins and calcium. Teens can be finicky eaters, however, and very often they rely on quick foods which are typically high in sugars. Thus, though your teen may take in many calories during the day, all too often these may be "empty" calories, in the form of sugar, which burn up quickly and don't help body growth. Obesity, too, may become a health problem for some teens. While a highly active teen may burn up all the calories eaten, those teens whose daily calorie intake exceeds their energy output may have serious problems with accumulating fatty tissue. The best way for teens (and adults too!) to control obesity is to increase their activity level and to eat more foods contain body strengthening protein and calcium and fewer foods containing sugars and fats.

Fatigue is a problem for many teens. A growing and changing body uses a great deal of energy. Incorrect diet and lack of adequate rest can affect the teenager quite severely. Encouraging your teen to eat well, sleep longer, or rest for short periods during the day should prevent excessive fatigue.

One of the most obvious problems experienced by teens is skin blemishes. Acne affects about 85% of all teenagers. Although common, unsightly acne is very difficult for the teen to live with. Acne is caused by an imbalance of hormones in the body. Oil glands become more active, and oily skin produces blackheads or pimples. If the surrounding skin is irritated, the oil sacs break and result in acne. Most doctors agree that the best treatment for ordinary acne is keeping the face very clean and keeping fingers away from any blemishes. If your teen has severe acne, however, it's a good idea to have a doctor see it because severe acne can leave scars.

Accidents are a serious problem for teenagers. In fact, accidents are the greatest single cause of death among adolescent boys, especially those aged 15 to 19. These boys often have a daring attitude because of their increased size and strength; unfortunately, they do not have comparable emotional strength and good judgment. High school athletics also are a common cause of injury for teens. Lack of coordination to go along with the great strength may cause problems, as well as a tendency to patch up the "hero" and send him or her back into the game.

All of these health problems can be avoided by the teen whose parents are helping with their awareness and their exercise of good judgment. Encouraging the teen to continue to practice the good health habits learned in childhood can do much to avoid serious health problems.

There's No Set Timetable for Change

When your child was quite small, you were constantly reminded not to compare him or her to the child next door. Babies begin to walk and talk at different ages and, unless a child is seriously "off schedule" or has noticeable problems, the parent need not worry if the child develops certain skills sooner or later than other children. The same advice holds true for teenagers. As people mature, there is even greater variability in their abilities and their size. For example, tall and short fourth graders may differ by only a few inches, while tall and short men may differ by a foot or more. The age at which young people begin to mature varies greatly although the growth spurt begins earlier, the rate of growth is faster, and maximum growth is reached about 2 years earlier than it was 2 or 3 generations ago. The variability among individuals may cause great concern to teens, especially those who are maturing much earlier or much later than most of their friends. A little girl whose friends are already past training bras while she is still flat-chested, or a boy whose friends are suddenly adult men in appearance while he is still boy-like may suffer a great lack of self-confidence and worry about "lateness." On the other hand, the early maturing boy or girl also stands out and may be additionally burdened by expectations that since he or she looks like an adult his or her behavior will also be adult-like. The informed, concerned parent can do a great deal-through sympathy and reassurance -to help the young teen get through this difficult time until he or she begins to look more like everyone else.

Your teen is now or will soon be going through one of the most exciting and frightening periods of life. Your support and concern at this time can do a great deal to cement happy relationships which will continue through the years of growth and change ahead.


Thornburg, H.D. Development in Adolescence. Monterey, CA. Brooks/Cole, 1975.

White, K. M., and Speisman, J.C. Adolescence. Monterey, CA: Brooks/Cole, 1977.

Judith 0. Hooper is assistant professor of family studies, School of Family Resources and Consumer Sciences, University of Wisconsin-Madison and Division of Professional and Human Development, University of Wisconsin-Extension.

RR 7/90

In cooperation with NCR Educational Materials Project.

Issued in furtherance of cooperative Extension work, Acts of congress of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture and cooperative Extension Services of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio and South Dakota. Gale L. VandeBerg, Director, Cooperative Extension Service, university of Wisconsin, Madison. Programs and activities of the cooperative Extension Service are available to all potential clientele without regard to race, color, sex, national origin, or handicap.