Is My Penis Too Small?
Micropenis, Inconspicuous Penis Less Common Than Small Penis Syndrome
How to Measure a Penis continued...
Did you get five and a quarter inches? If so, you are exactly normal. Most adult men are within about a half inch of 5.24 inches, according to statistics Palmer has compiled. Nearly all studies of penis length come up with a similar measure.
If you're a little smaller than that, you've got lots of company. Just as many men are below average penis size as above it.
How big is big? According to Palmer's statistics, only 0.6% of men have an SPL of 6.8 inches or more. But too big isn't what men tend to worry about.
Micropenis: When a Penis Really Is Too Small
There is, of course, such a thing as a very small penis. The medical term "micropenis" applies to the 0.6% of men with the smallest penises. According to Palmer's statistics, an SPL of three and two-thirds inches or less indicates a micropenis.
Even then, U.S. doctors hesitate to recommend surgery for a man whose SPL is longer than three inches. That's because surgery is controversial and risky.
Micropenis isn't usually something a man discovers when he's an adult. It's usually caused by genetic or hormonal abnormalities that cause other, more serious health problems early in life.
That's because the penis starts to develop when a fetus is just 8 weeks old. By week 12, the penis has developed and begins to grow. During the second and third trimesters, male sex hormones cause the penis to grow to normal length. Factors that interfere with hormone production and hormone action stunt penis growth.
When discovered in infancy, micropenis can be treated with testosterone, which can stimulate penis growth in childhood, even after puberty. While the safety and long-term efficacy of this treatment remains to be proved, available data suggest the treatment does not affect normal development during puberty.
For adults with micropenis, the options are few.
"For true micropenis, there is not much you can do that is adequate for the adult patient, except for putting in a penile prosthesis," Gilbert says.
Fortunately, micropenis is a rare condition. Far more common is what Palmer and colleagues call "the constellation of conditions that make the penis look diminutive and small" -- inconspicuous penis.