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.
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.