#Letstalktoourboys | When your boy grows up

A : Aerial View

What are the stages of puberty?

An overview of physical changes that boys go through during puberty.

by Dr Sweta Bajaj

Puberty is a crazy time and occurs through a long process, beginning with a surge in hormone production, which in turn causes several physical changes. Every person’s timetable for puberty is different. Below is an overview of some physical changes boys can expect during these years.

Enlargement of the Testicles and Scrotum

A near doubling in the size of the testicles and the scrotal sac announces the advent of puberty. As the testicles continue to grow, the skin of the scrotum darkens, enlarges, thins, hangs down from the body and becomes dotted with tiny bumps. These are hair follicles. In most boys, one testicle (usually the left) hangs lower than the other.

Facial hair

The appearance of facial hair typically starts by the age of 13, or when a young man hits puberty. Among other things, the testosterone level greatly determines the chance of growing facial and body hair. At a young age, boys develop thin facial hair. As they mature, these thin hair becomes thicker and blacker in color due to the rising level of testosterone. As the facial hair grows, hair under the arms, on the chest and near the reproductive organ also develops. Conversely, a low testosterone level can account for the weak growth of facial hair.

Pubic Hair

Fueled by testosterone, the next changes of puberty come in quick succession. A few light-coloured downy hairs materialize at the base of the penis. As with girls, the pubic hair soon turns darker, curlier and coarser in texture, but the pattern is more diamond-shaped than triangular. Over the next few years, it covers the pubic region, then spreads toward the thighs. A thin line of hair also travels up to the navel. Roughly two years after the appearance of pubic hair, sparse hair begins to sprout on a boy’s face, legs, arms and underarms, and later the chest.

Changing Body Shape

A girl’s physical strength virtually equals a boy’s until middle adolescence, when the difference between them widens appreciably. Boys tend to look a little chubby and gangly (long arms and legs compared to the trunk) just before and at the onset of puberty. They start to experience a growth spurt as they progress further into adolescence, with the peak occurring during the later stages of sexual maturation. Body proportions change during this spurt, as there is the rapid growth of the trunk, at the legs to some extent too. Boys continue to fill out with muscle mass long after girls do so that by the late teens a boy’s body composition is only 12 per cent fat, less than half that of the average girl’s.

Penis Growth

A boy may have adult-size genitals as early as age thirteen or as late as eighteen. First, the penis grows in length, then in width. Teenage males seem to spend an excessive amount of time inspecting their penis and covertly (or overtly) comparing themselves to other boys.
Most boys don’t realize that sexual function is not dependent on penis size or that the dimensions of the flaccid penis don’t necessarily indicate how large it is when erect. Parents can spare their son’s needless distress by anticipating these concerns rather than waiting for them to say anything since that question is always there regardless of whether it is articulated. In the course of a conversation, you might muse aloud, “You know, many boys your age worry that their penis is too small. That rarely turns out to be the case.” Consider asking your son’s paediatrician to reinforce this point at his next checkup. A doctor’s reassurance that a teenager is “all right” sometimes carries more weight than a parent’s.


Boys are considered capable of procreation upon their first ejaculation, which occurs about one year after the testicles begin to enlarge. The testicles now produce sperm in addition to testosterone, while the prostate, the two seminal vesicles and another pair of glands (called Cowper’s glands) secrete fluids that combine with the sperm to form semen. Each ejaculation, amounting to about one teaspoonful of semen, contains 200 million to 500 million sperm.

Wet Dreams & Involuntary Erection

A nocturnal emission, or “wet dream,” is not necessarily the culmination of a sexually oriented dream. See Nocturnal Enuresis in Teens.

What parents can do to help:

Explain to your son that this phenomenon happens to all boys during puberty and that it will stop as he gets older.

Emphasize that nocturnal emission is nothing to be ashamed of or embarrassed.

Note that masturbation is normal and harmless, for girls as well as boys, as long as it is done privately.

Erections, too, are unpredictable during puberty. They may pop up for no apparent reason—and seemingly at the most inconvenient times, like when giving a report in front of the class. Tell your teen there’s not much he can do to suppress spontaneous erections (the time-honored technique of concentrating on the most unsexy thought imaginable doesn’t really work), and that with time they will become less frequent.

Voice Change

Just after the peak of the growth spurt, a boy’s voice box (larynx) enlarges, as do the vocal cords. For a brief period, your son’s voice may “crack” occasionally as it deepens. Once the larynx reaches adult size, the cracking will stop. Girls’ voices lower in the pitch too, but the change is not nearly as striking.

Breast Development

Early in puberty, most boys experience soreness or tenderness around their nipples. Three in four, if not more, will have some breast growth, the result of a biochemical reaction that converts some of their testosterone to the female sex hormone, estrogen. Most of the time the breast enlargement amounts to a firm breast bud of up to 2 inches in diameter under the nipples.  Occasionally, this may be more extensive, resulting in profound “gynecomastia.” Overweight boys may have the appearance of pseudo-gynecomastia (lipomastia), due to excess fatty tissue on the chest wall.

As you might imagine, this development can be troubling for a child who is in the process of trying to establish his masculinity. If your son suddenly seems self-conscious about changing for the gym or refuses to be seen without a shirt, you can reasonably assume that he’s noticed some swelling in one or both breasts. (One particularly telltale sign: wearing a shirt to go swimming.)

So sit with your boy and tell him that these physical changes are normal so that he doesn’t go around collecting wrong information or is troubled to have no knowledge at all.    

(Dr Bajaj is a dentist, certified lactation consultant and childbirth educator.)


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