Politics of the Penis

Brian Mautz has had a big week. Since his paper on the importance of penis size in attractiveness judgements was published in PNAS on Tuesday morning, news outlets and blogs have proved near-insatiable. The story mutated, and the mutants proliferated so wildly that many accounts bear only faint resemblance to the paper he published a few short days ago.

When he hasn't been fielding interview requests, he's been wading through the mostly unsolicited mail, much of it hostile and a great deal of it "not safe for work" (even the work of a guy who studies penis evolution and mate choice).

here and at
. In the intervening week, readers have engaged in a mostly sensible discussion about the paper and my analysis of it. There was, as expected, plenty of discussion about the paper's limitations:
  • Ratings from a sample of women who represent only a small and rather non-random slice of humanity
  • The fact that the authors manipulated only three traits (height, torso shape and penis size), but there are so many more dimensions to attractiveness
  • The fact that the penises were flaccid, and that flaccid size is only a poor predictor of erect length and, especially, girth (see footnote)

These limitations and the many others raised by thoughtful readers reflect the dilemma of doing research in this sphere. You cannot study every nuance of attractiveness at the same time and still have the statistical power necessary to gain interesting insights. But this frustrating reality often gets readers' backs up when they read a news article that trumpets the importance of, say, penis size.

There is a difference between saying "penis size matters" and "penis size is the only thing that matters." I read the PNAS paper pretty closely, and it stuck faithfully to the former tack. But somewhere along the way, in all the breathless enthusiasm, a lot readers took the second message.


While this neatly executed and necessarily constrained study of human penis size revealed something about human behavior, the truest insights into human nature came from the responses to the paper.

In my analysis piece I mentioned that public discussion about penis size seems reflexively to opt for what I called "the Goldilocks cop-out":

Most media stories on the topic of penis size conclude that as long as the penis in question isn't way too big or way too small, it's likely to be "just right".

And within the large zone of "just-rightness", few commentators are willing to claim that size really matters.

Consider how Nature, arguably the world's most august scientific journal and news outlet, portrayed the story:

Nature ran with the rather bizarre and altogether wrong headline "Bigger not always better for penis size" (screenshot from nature.com).

Whatever you think of the limitations of the PNAS study, it did not claim that "bigger is not always better." In fact, it showed that larger penis sizes are more attractive, although the incremental rise in attractiveness was not as fast near the top of the size distribution as it was near the bottom.

So strong is the urge to mollify male insecurity or, perhaps, to dampen rampant phallocentrism that Nature saw fit to somehow imagine that this paper said something that it most certainly did not. Goldilocks doesn't get any more confused than that.


A lot of the reaction that Mautz and his collaborators elicited illustrates the conflict that so many people feel about the subject. On the one hand, stories about penis evolution exert a compelling, voyeuristic pull, but on the other, they also elicit a repulsion and an urge to protest -- perhaps just a little too much, methinks.

As Brian Mautz put it to me in an email:

The amount of media [the paper] garnered speaks volumes about how interested people are even though some people claim it was a frivolous or pointless study. It also highlights how taboo talking about penises is to everyone. I doubt it would spawned over 1400 news article in 48 hours if it wasn't so taboo.

So taboo, in fact, that Facebook took offense at the main image of the avatars used in the study. Both Discover and Scientific American magazines found themselves on the wrong end of the Facebook fun police, who deemed the image offensive and took it down.

Image from the Facebook page of Discover magazine, after the original image was taken down by Facebook because it was, apparently, offensive.

I can see how the penis pics, even though they are on humanoid greyscale avatars rather than real people, could be confronting. And I'm grateful to Facebook for valiantly attempting to maintain some kind of standards in their shrinking corner of the Internet.

But Facebook have form when it comes to leaden-footed censorship decisions, particularly pictures of breastfeeding (see the delightfully subversive "Breastfeeding Photos are NOT Obscene" page). In rushing to censor the images accompanying a science story that is explicitly about penises, Facebook look a little lost.

Brian Mautz tells me:

CNN also had it on their front page this weekend (in the "Just for Fun" section sort of ironically). They too started off with the photo of figure 1 as the associated picture, but it had been replace by the end of Saturday with an innocuous picture of two meters stick. I suspect it is because readers complained.

Intriguingly, The Conversation's Facebook page hasn't been censored yet. It has long been my ambition to be banned by some withering institution like Facebook or the Vatican. Perhaps one of you who has made it this deep into the article might want to complain?

The image remains ... intact ... on The Conversation's Facebook page.

We biologists tend to underestimate how squeamish other people get about body parts and functions. I'm intrigued now to read about penis taboos and the psychology behind them. One criticism that emerged again and again in this discussion about the penis paper was that scientists should turn their attention to the study of breast size or vaginal dimensions.

Those who would claimed that men are victims, here, of a double standard, might have done well to search the scientific literature, or to look a popular culture.

Breast size (and shape, and "bounciness") has received far more than its share of attention. And often the reporting is far less sensitive to the delicate nature of the topic and the potential to offend.

Casual conversations with colleagues give me the distinct impression that it is far easier to gain ethics committee approval to study women's breasts than men's penises. And that's just the flaccid kind.

And frontal nudity in the cinema seems to be far more common when the nude in question is a woman.

And yet squeamishness about nudity, and about penises in particular, is far from uniform. It follows fashions, and cultural norms seem quite malleable. Sculptors and painters in some periods show a deep fascination with genital anatomy, whereas others show an equal fondness for the leaf of the fig tree.

My friend and colleague Karl Vernes, who conducts field work in Bhutan, sent me several images of painted houses and businesses there, including the one below.

Paintings adorning a restaurant in the town of Nobding, Bhutan (photo by Karl Vernes)

Apparently the phallus paintings that adorn many Bhutanese houses and shops date back to the late 15th century to a buddhist teacher, Drukpa Kunley, variously known as "the divine madman" or "The Saint of 5,000 Women." He traveled the country simultaneously teaching Buddhism and conferring his blessing -- in the form of sex -- on women who sought it. He is considered a saint of fertility, and the images are nowadays considered fertility symbols.

I wonder how Facebook would deal with that?

Much Ado About Penis Size

I am impressed that a single scientific paper such as the one by Brian Mautz and his colleagues reached so many people. I am decidedly pleased that it made an impact and perhaps got people talking and thinking. And I hope it persuaded some people that science can be a lot of fun.

That would be a lasting positive contribution that might outweigh the specifics of what this study said (and is incorrectly alleged to have said) about the importance of penis size.

Footnote: The published literature shows that flaccid size is a pretty good predictor of "stretched length", and that stretched length is a good predictor of erect size. Perhaps this is part of the Goldilocks effect? (A famously profane evolutionary biologist is alleged to have said about the idea that flaccid size doesn't predict erect dimensions: "That sounds like something small-dicked guys would say.")

Rob Brooks does not work for, consult to, own shares in or receive funding from any company or organization that would benefit from this blog post and has no relevant affiliations.

This blog post was originally published at The Conversation. Read the original blog post.