For most boys, puberty starts around age 11 and lasts until around age 17. But it can start earlier or end later. Just as it is with girls, the changes in boys' bodies and emotions are the result of hormones, but the boys are reacting to different hormones. One hormone in boys' bodies is testosterone (tes-TOS-tur-own), which causes changes in boys' bodies, like hair growth on boys' chests, legs, faces, and under their arms, and the growth and development of the penis and testicles (external genitalia). Hormones are responsible for making oil and sweat glands function, and they can change the way boys feel and act.

Many signs of puberty are easy to spot. Boys' voice boxes, or larynxes ("Adam's apple") grow, so their voices start to crack and squeak before they deepen. Their muscles develop and they experience growth spurts that make them taller. Also, at point between the ages of 11 and 17, boys will begin to grow facial hair and need to shave.

Testosterone makes males capable of producing sperm, which are tiny cells that can fertilize a female's eggs to create babies. Sperm travel through the penis during sexual intercourse.

Like girls, boys going through puberty to pay special attention to hygiene. Boys need to bathe or shower more frequently than they did before puberty. They also need to get plenty of rest and exercise.

Just as girls are often concerned with their breast development and other changes in their private parts, boys have emotional reactions to the physical changes they're going through. The important thing to remember is that all people, boys and girls alike, go through intense changes during puberty, so it's best to be patient and tolerant of yourselves and of each other, to seek advice from parents, educators, and doctors, and to enjoy the process of growing up. There's plenty of time to be grown-ups later on!

Want to learn more about the changes boys go through during puberty?
Check out It's A Guy Thing® or frequently asked guy questions.