My obligatory post on penis size

When we wrote our first book on medical myths, our agent told us we had to “sex it up”. That’s how the first chapter of my first book came to be “Men with big feet have bigger penises”. This made for a problem when my then-five-year-old son opened his copy and nearly had his eyes bug out of his head.

This is also how a chapter in our second book on medical myths was entitled “You can make your penis bigger without surgery”. It’s how the first chapter in our third book on medical myths came to be “Penis size matters”. In fact, the first three chapters of the last book were about penises.

People are obsesses with penises, especially their size. Penises sell books. They evidently also get manuscripts published. “Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15 521 men“:

Objective: To systematically review and create nomograms of flaccid and erect penile size measurements.

Methods: Study key eligibility criteria: measurement of penis size by a health professional using a standard procedure; a minimum of 50 participants per sample. Exclusion criteria: samples with a congenital or acquired penile abnormality, previous surgery, complaint of small penis size or erectile dysfunction. Synthesis methods: calculation of a weighted mean and pooled standard deviation (sd) and simulation of 20 000 observations from the normal distribution to generate nomograms of penis size.

I imagine this is the definitive systematic review. Here’s the nomogram:


It’s small unfortunately, so let me break it down for you. If your erect penis is 4.7 inches, you’re at the 25th percentile. If your erect penis is 5.1 inches, you’re at the median. Half of men have bigger penises, and half have smaller. If your penis is 5.6 inches, then congratulations – you’re in the 75th percentile. If you have a six inch erect penis (which is what many people “think” is average, then you’re in the 90th percentile.

What’s striking here, though, is that most men are pretty much the same. The idea that seven inch penises are common appears to be – wait for it – a myth. Ninety-five percent of men have penises smaller than 6.3 inches. More than half of men have a penis that’s between 4.5 and 5.5 inches, and only 15% are smaller than 4.5 inches.

Everyone should stop worrying about this. I’d love to stop writing about it.


(h/t CommonHealth)

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