Teen Girls' Guide to Teen Boys

The physical and emotional changes teen guys go through.

Medically Reviewed by Hansa D. Bhargava, MD on January 10, 2012
From the WebMD Archives

You may be noticing guys more often than when you were a kid.

Understanding boys can be tricky. So here’s the inside scoop on what teen guys go through.

Physical Changes

Boys usually begin puberty between the ages of 10 and 15. That's two years later than most girls.

Starting at about age 12 or 13, and as early as 9, hormones called androgens bring on a number of physical changes, says Lori Legano, MD, assistant professor of pediatrics at New York University and attending physician for the adolescent clinic at New York's Bellevue Hospital Center.

One of the first things guys start to notice is that their testicles and scrotum (the sac located underneath the penis) start to get larger. Their penis gets longer and wider and pubic hair begins to grow in, too.

Legano says male hormones are the reason for a number of other changes. Maybe you’ve noticed some of these developments in the boys you know:

  • Hair has started to grow on their faces.
  • Hair under the arms starts to show up.
  • Body odor becomes an issue. 

Height Gap

Guys and girls have different timelines when it comes to puberty.

It breaks down like this:

Girls grow very fast (this could start as young as age 8), get their periods, their growth plates fuse, and they stop growing. Puberty over.

Boys, on the other hand, take their sweet time. They may not have a major growth spurt until age 15 or 16, and they sometimes keep growing into their early 20s.

That’s why around the 8th grade you have taller girls and smaller boys.

 “Boys are slow to grow but then they catch up later,” Legano says.


Puberty is the fastest you’ll grow, other than when you’re a little baby, says Marc Lerner, MD, of the University of California, Irvine.

All that change can be awkward at times.

“Guys are also sometimes uncomfortable with how their body is changing in terms of height, their physical strength, or acne,” Lerner says. And, guys who develop slower and are smaller than other boys may feel really stressed about it.

On top of that, boys’ voices become deeper and may start to crack. Guys can blame their growing larynx, or voice box, for that.

If a boy seems pretty shy about talking to you or speaking up in class at this age, it could be that he feels awkward about his voice.

Cut him some slack -- wouldn’t you clam up if you were worried about your voice failing you in public?


Sex and the Power of Hormones

The same male hormones that brought on hair growth and B.O. also stir up new sexual urges.

“Girls might notice boys paying more attention,” Legano says.

Strong thoughts about sex, Lerner says, sometimes “lead to intense focus and intense but brief connection, which may pass very quickly.” That’s often confusing, he says.

All these thoughts lead to lots of erections, when the penis fills with blood and becomes hard. And, it can be tough for guys at this age to control them.

It takes some time for guys (and girls) to sort out all the thoughts and feelings they’re having about sex and to figure out who they are, but it’s a normal part of growing up.

Give a Guy a Break

If you think boys are so immature, think again.

The guy who may have a hard time talking with you may not be confident or he may not be an awesome communicator -- yet.  Guys (and girls) start to show more empathy, mature social skills, and have more intimate relationships around age 17. That’s when the frontal lobe of the brain, which plays a big role in self-control, develops more fully.

Boys who "may seem immature, shy, and not socially mature will develop soon and become more comfortable with themselves,” Legano says.

Your best bet is to be kind to people -- guys or girls -- and think about who they're becoming, not just who they are right now. That's part of growing up, too.

Show Sources


Marc Lerner, MD, chief of developmental and behavioral pediatrics, University of California, Irvine.

Lori Legano, MD, assistant professor of pediatrics, NYU; attending physician, adolescent clinic, Bellevue Hospital Center, New York.

Medline Plus: "Adolescent Development."

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