Dear mr_dubble0_MOB,

It can take up to 20 years of age for all the changes that occur in puberty to take place. Puberty doesn't happen all at once — it happens in stages. So a girl or boy may show some signs of puberty at an early age (like breasts beginning to grow or a voice that's starting to crack), but may not show other signs of puberty until she or he is much older (like getting a period or growing facial hair).

Boys usually start puberty between 10 and 17 years old. It is common for puberty to start when boys are around 12 years old, though some may start a little sooner and others considerably later. The changes happen because your body releases several different hormones. The first sign is that your testicles get bigger. Within about a year after that, your penis gets larger, and pubic hair starts to grow.

One of the biggest concerns for many guys is the size of their penis. There isn't a normal size for any particular age. However, 90 percent of all adult erect, or hard, penises are between five and seven inches long. Also, the size of a guy's penis when it's flaccid ("soft") doesn't really have anything to do with what it will be like when it's erect ("hard"). As they become erect, smaller flaccid penises tend to grow more than penises that are larger when they're flaccid.

Hope this information helps!

Take care,

teenwire.com^® Editors

This column is for informational purposes only and is not intended to constitute medical advice, diagnosis, or treatment. If you have a medical problem, please call toll-free 1-800-230-PLAN for an appointment with the Planned Parenthood health center nearest you.