During puberty, the penis will grow in both length and girth. Once puberty ends, there is unlikely to be any further penile growth. That said, some males may experience growth into their early 20s. Many males have concerns about the size of their penis at some point.

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Greene, my month-old son has a recessed penis. Ever since we had him circumcised, the penis has recessed into a pad of fat surrounding it. In order for it to emerge, we have to push on either side of the pad. Our pediatrician assured us that as he thinned out, it would emerge on its own.
Dr. Greene's Answer
The girth circumference of a flaccid penis and an erect penis average about 3. The length and girth of a flaccid penis changes frequently, primarily based on temperature. A flaccid uncircumcised penis that still has its foreskin may look a little bigger than a flaccid circumcised penis. Puberty is actually the second time in your life when your penis goes through a growth spurt. During the first year of life, penis length and girth grow significantly. At puberty, the penis and testicles grow more rapidly. The puberty timetable is different for every person.
Puberty — it's a crazy time and occurs through a long process, beginning with a surge in hormone production, which in turn causes a number of physical changes. Every person's individual timetable for puberty is different. Below is an overview of some physical changes boys can expect during these years. A near doubling in the size of the testicles and the scrotal sac announces the advent of puberty.