Puberty is the process of physical changes leading to physical sexual development as well as complete body growth.
During puberty, your whole body goes through growth spurts until it has become physically mature in terms of bone mass and size, and the sexual organs and secondary sexual characteristics develop and mature. Chances are, if you're at this website, you have likely already started puberty. If you’re in your late teens or early twenties, you may even be finished at this point.
On average, puberty begins for girls between the ages of 8 to 11 (but in some girls as early as age six), and a couple years later for boys, usually between the ages of 11 and 14. Puberty is currently considered to be precocious, or early, if it begins before the age of 8 for girls and age 9 for boys.
Most people are completely finished with puberty by the time they're through their teens and have reached their twenties, though plenty complete the process earlier, and some later. Many adolescents assume that puberty finishes earlier than it actually does, while many adults assume that it lasts longer—finishes later—than it usually does. Puberty doesn't start and end with breast growth and getting a period, or with a voice that has deepened. Overall, the entire process takes a handful of years to complete, and tends to occur in a similar order for everyone, though for intersexed individuals, development during puberty may vary .
Puberty is happening earlier at this point in history for many, especially for girls, than it has at other times: it typically begins six whole years earlier now than it did on average less than 200 years ago. There are a lot of theories for why that may be -- diets which are primarily or entirely animal based (including the hormones, like bovine growth hormone, often used in factory farming), environmental estrogens, pesticides and preservatives in many foods, unhealthy weights and eating habits, as well as positive changes in nutrition -- but as of right now, all we really know for sure is that it happens earlier than it used to for many: we've yet to have sure answers for why it happens.
The timetables below are best viewed from a standpoint of what is happening, rather than when it's happening. You may find that you reach or have reached a certain stage earlier or later than a typical age, and that's okay. If you keep up with annual physicals from your regular doctor, he or she can address any concerns you might have if you're worried you're starting development too early or too late.
Breasts: The usual evidence puberty has begun in girls is initial breast growth, called breast budding, because the first breast growth happens with small nodules or lumps just under the nipples (and not always at the same time, but sometimes one before the other). Over the course of puberty, as the breasts grow and develop further, it's normal for developing breasts or breast buds to feel tender, or even hurt a little. Breast development is going on through the whole of puberty, including changes in the size and shape of the aureola, or nipple area. By the end of puberty, breasts will be the basic size and shape they'll have through most of life, but some changes do still occur over time, due to age, hormonal changes, levels of body fat, gravity, and pregnancy and childbearing, if and when those occur (and FYI: brassieres have NEVER been shown to make any difference per breast aging and changes over time).
Body and pubic hair: About six months after breasts begin to develop, pubic hair and other body hair will usually begin to appear. In some young women, pubic hair may appear before breast budding. Pubic hair (which usually covers the mons, outer labia, the area between the buttocks and some of the inner thighs), hair in the armpits, and hair on the legs, is typically thicker, darker and coarser than other body hair.
Menarche: The menstrual cycle begins during puberty, usually about two years after breast budding, starting with first ovulation (which is pretty undetectable) and then showing itself with the first period, called menarche. Most young women now begin to menstruate between the ages of 9 and 16. If a young woman is seriously underweight, malnourished, excessively dieting, overexercising or has an eating disorder, that may delay menstruation because a certain amount of body fat is needed for menses to occur. For the big skinny on periods and menstruation, see On the Rag: A Guide to Menstruation
Vulval changes: Like with the penis and testicles for boys, the vulva grows larger and will start to look more pronounced than it did in childhood. The color of parts of the vulva often changes or becomes darker, and our inner labia become more obvious, both due to growth and because the other genital changes alter the way the mons sits atop the vulva.
Body size and shape changes: Through the course of puberty, the body will both grow taller and change shape. Generally, around menarche, young women will have done much of their peak growth in terms of height and bone mass (while for young men, height and bone mass growth tends to be what's finished last).
As body shape and size develops, it's typical to look a little weird, or feel like you're wearing someone else's skin for a while. The extremities, arms and legs, feet and hands, often grow faster than the rest of the body, for instance. As your hips are widening and you're building up body fat (which you need to menstruate and fully mature), sometimes you may find you look or feel pretty awkward, and that body fat decides to live in weird-looking places for a while. By the time you're through with your teens, it'll all even out.
Growth spurts: Puberty in boys usually begins with a massive growth spurt. As with girls, it's normal for the extremities to grow faster than other parts of the body, and to feel a bit gangly while that's going on. Because puberty starts later in boys than in girls, it's typical for young men to be shorter than their female friends of the same age for a while. Through puberty, though, young men will become taller. Muscle mass often increases pretty rapidly (even if you can't tell that it is), and it's normal to be gaining a good deal of weight.
While men don't have breasts like women do, it is common to experience nipple swelling, and larger young men may see some actual breast development. That's also okay.
Penis and testicles: During puberty, the penis and testes grow to their adult size. Until puberty is complete, neither is development and growth of the penis and testes, and that can not be fully complete until you're as old as 20, sometimes even a little older. It's common for the length of the penis to grow faster than the width of the penis, and for testicle growth to start before penis growth.
Erections usually begin before ejaculation does. It's normal to be able to achieve erections before the ability to ejaculate, sometimes with a lapse between of a few years. Some young men don't start to ejaculate until their late teens (which doesn't mean, however, it's safe to have unprotected partnered sex). During puberty, erections often occur very frequently and involuntarily, something that is a source of embarrassment for many young men, but it's completely normal and does happen to everyone. When ejaculation begins, it's typical to have wet dreams, or nocturnal emissions, ejaculation that occurs while sleeping due to sexual dreams, stimulation from sheets and blankets, and/or having a full bladder. Young men who masturbate less than others may experience more wet dreams.
Body and pubic hair: Pubic hair is usually the first adult body hair to start cropping up, and usually continues growing around the anus, buttocks and legs. Growth of underarm hair usually follows. Chest and facial hair often develops last or even after the end of puberty. Not everyone has the same patterns of body hair, that's based mainly on genetics. So, while some grown men will be very hairy all over -- including areas like the back and upper arms -- others may have sparser body and facial hair, and may not ever have much chest or facial hair. An entire range is normal.
Voice changes: During puberty, the male voice deepens, and may go through stages of being all over the place. At times, you may find it hard to "find" your voice, or experience cracking or croaking.
Skin changes: Hormonal changes in your body often show up in your skin, and glandular growth and causes new issues as well. As both young men and women go through puberty, it's normal for the skin to become oilier, and for perspiration and body odor (AKA: B.O.) to become stronger, because you've got hormones shuttling through your body at levels they weren't present in before. Adolescent acne (pimples and zits), suck as it may, is as common as the sun in the sky.
Puberty is stressful for plenty of people, and that often goes unacknowledged. While the development that's happening due to puberty is largely physical, not only is a lot of emotional and social development also going on, all the changes that go on during puberty create emotional and social issues as well. It can be hard to have your body changing so much and so uncontrollably. Accepting phases that are far outside the physical ideals -- or ideas about what bodies should look like to be "perfect" in full-grown adults -- isn't often easy.
It's normal and common to feel awkward, clumsy or to have body image issues during puberty. People gain weight as a necessary part of puberty (and teenagers, because of this process, actually need more calories in a day than any other age group), and that can be hard in a culture and/or in peer groups where thinness is idealized. Acne, voice changes, body hair, various stages of breast development (or slow development), unwanted erections for young men and unexpected or inopportune menses in young women can all be sources of body image issues. Adults and peers, intentionally or without even realizing they're doing it, may call attention to your changing body, making you feel embarrassed or in the spotlight. A parent may feel a young girl needs a brassiere before she wants one yet (or if she ever wants to wear one at all), or inadvertently make public a teen boy's wet dreams, and things like that can really bump up the social discomfort of puberty.
Our bodies feel pretty simple during childhood. We don't have to worry about things like body odor, acne or menstruation, for instance. Sexual feelings and maturation, and the attention from others that comes with those things, can be very uncomfortable. Plenty of people going through puberty have times when they truly hate their bodies, or feel that certain developing parts -- like breasts, pubic hair or erections -- are gross, and feel ashamed of them. Some people may even wish they could avoid becoming adults altogether, physically and otherwise. The ideas other people have about our bodies as they're developing can be hard to deal with sometimes: like insistence we should be excited or public about development we aren't thrilled with at all, or that we should hide things we either really can't hide, or don't want to keep hidden.
For teens who either start developing far earlier or later than most of their peers there are special and often increased stresses. Late bloomers may feel like children -- or be treated like them -- compared to their friends or siblings. Those who develop early may find themselves the center of a lot of unwanted or inappropriate sexual attention or teasing. Since boys start puberty later than girls, and many girls aren't aware of that, they may encounter expectations of sexual development, functions or desires from their female peers that aren't yet appropriate for them or wanted.
Puberty -- and how our individual bodies go through puberty -- is unavoidable. Our bodies are designed to mature and grow into adult bodies. We can't avoid puberty, or healthfully try and curb certain parts of it -- excessive dieting, for instance, in an attempt to prevent normal weight gain or breast development, or to try and make menses stop, is only going to make you sick over time, not keep development from happening. We also can't make it hurry up with herbal supplements, hormones, weight training or by behaving in certain ways. Parents having a hard time with their teens: puberty or adult development can't make it go away or slow down by keeping teens in childhood clothing or activities, or by pretending it isn't happening.
Puberty has its own timetable for everyone, and no matter what you do, it's going to stick to that individual schedule. It's ornery like that.
While puberty can feel like it goes on forever, it really doesn't. It only goes on for, at most, about 1/15th of your entire life: usually, for less time than you spent in elementary school. Puberty is temporary: it does end, and you only have to go through it once. That isn't to say your body will never go through changes again in your life, because it will, but outside of pregnancy, you can rest assured it'll never likely go through SO many changes in such a short period of time ever again.