Is penis size and race really uncorrelated?

I’d guess probably not? Penis size is correlated with height, and height is also correlated with race, so it’d be weird if there were no correlation whatsoever between penis size and race, just based on sheer physical size differences alone. Maybe it’s a super slight correlation, but we should see something, right?

My friend said “Hey, there’s no correlation between penis size and race” and linked Wikipedia:

The belief that penis size varies according to race is not supported by scientific evidence.[6][30] A 2005 study reported that “there is no scientific background to support the alleged ‘oversized’ penis in black people”.[31]

A study of 253 men from Tanzania found that the average stretched flaccid penis length of Tanzanian males is 11 cm (4.53 inches) long, smaller than the worldwide average, stretched flaccid penis length of 13.24 cm (5.21 inches), and average erect penis length of 13.12 cm (5.17 inches).[32]

A 2016 study of 248 Korean men identified the average erect penis length to be 13.53 cm (5.33 in).[18] A study of 115 men from Nigeria found that the average flaccid stretched penis length of Nigerian males is 13.37 cm (5.26 inches) long, which is near identical to the worldwide average, stretched flaccid penis length of 13.24 cm (5.21 inches) and average erect penis length of 13.12 cm (5.17 inches).[33] A 2015 systematic review of 15,521 men found “no indications of differences in racial variability”, and stated that it was not possible to draw any conclusions about size and race from the available literature and that further research needed to be conducted.[1]

According to Aaron Spitz, a urologist, many websites and studies promoting variation of penis size between races use unscientific methods of collecting information and often ignore contradictory evidence. He concludes that “when you really take a good look at the naked data, there’s not a whole lot there [showing racial variation in penis size].”[34]

Uh, what? This is extremely confusing to me. Does this mean taller men (and thus taller races) have smaller penises relative to their body size, and shorter men (and thus shorter races) have larger relative to their body size? If that were true, it’d be uniquely interesting and I wanna figure out why!

But I suspect it’s not true, and that Wikipedia (or the literature it’s based on) has some incentive to deny that race and penis size have any correlation at all, so I took some adderall.


The belief that penis size varies according to race is not supported by scientific evidence.[6][30]

The source here is an article that describes a study, saying “The findings also deflate a few other myths about male genitalia. The notion that penis size varies according to race, for example, is false.”

The study itself, however doesn’t investigate race correlations whatsoever; it has a single mention of ‘race’, and it’s to say “More research is required on the effects of race and age on penile length”

A 2005 study reported that “there is no scientific background to support the alleged ‘oversized’ penis in black people”.[31]

The full context of this quote is “Interestingly, there is no scientific background to support the alleged ‘oversized’ penis in black people. Mean penile flaccid length and stretched length recently reported in 123 Korean military men were indeed lower than other values on non-Asian populations [5] (Table 1). At present, in the absence of any comparative study, these values remain debatable, but the possibility of racial differences in penile size should not be overlooked when investigating patients complaining of a short penis.”

Which I interpret as, “We haven’t seen studies saying black people have bigger penises, but there might be some evidence for penis size correlation in other races.”

A study of 253 men from Tanzania found that the average stretched flaccid penis length of Tanzanian males is 11 cm (4.53 inches) long, smaller than the worldwide average, stretched flaccid penis length of 13.24 cm (5.21 inches), and average erect penis length of 13.12 cm (5.17 inches).[32]

But if you continue reading, it says that their findings were out of the norm for other studies, probably due to stunted growth:

In this sample the mean SD adult stretched penile length of 11.5 1.6 cm is near the lower end of the spectrum of other studies. In the world literature length varies from 9.6 to 16.7 cm.15,17,19 –23 Our findings differ from published studies in West Africa.15,16 There are several potential explanations, including delayed puberty, stunted growth/poor nutrition and a preponderance of young adults in the adult category.”

(also, they do find correlation between glans circumference and height in this study)

But even if we take the Wikipedia summary at face value, then is it claiming that Tanzanian men have smaller penises than average? Wouldn’t this be dangerously close to suggesting there’s some racial correlation with penis size anyway?

A 2016 study of 248 Korean men identified the average erect penis length to be 13.53 cm (5.33 in).[18]

This study is specifically about the effects of circumcision on erect penis length (and also find a mild correlation of penis size with height). I think Wikipedia included this in an attempt to show “Look, different studies of subpopulations break stereotypes!”

But this meta analysis on penis length says there’s high variability across reports of penis length, because people usually measure penis length by stretching the flaccid penis, and it’s hard to know if people are putting the same amount of penis stretching force across different studies.

From the same meta analysis: “The question of racial variability can only be resolved by the measurements with large enough population being made by practitioners following the same method with other variables that may influence penis size (such as height) being kept constant.”

They want to control for height, the most plausible explanation for correlation between race and penis size? If people were claiming “There’s no correlation of penis size between races as a percentage of their height or body mass”, I’d be fine. I’m not sure if it’s true, but it seems like a really plausible theory. But people are claiming there’s no correlation between penis size and race at all, which seems ridiculous.

A study of 115 men from Nigeria found that the average flaccid stretched penis length of Nigerian males is 13.37 cm (5.26 inches) long, which is near identical to the worldwide average, stretched flaccid penis length of 13.24 cm (5.21 inches) and average erect penis length of 13.12 cm (5.17 inches).[33]

Again, this is a study (small sample size) that is subject to the same problems of the Korean study; hard to be consistent with penis measuring, and is why the meta analyses continue being “idk hard to draw conclusions.”

The study didn’t find a correlation of penis size with body mass, but did find a correlation of penis size with butt size. Bigger butts = bigger penises, which is new thing to watch out for, ladies.

A 2015 systematic review of 15,521 men found “no indications of differences in racial variability”, and stated that it was not possible to draw any conclusions about size and race from the available literature and that further research needed to be conducted.[1]

This is the same meta analysis I referenced saying that it’s hard to measure penis sizes, cause it’s hard to compare independent studies to each other (which is exactly what the rest of this Wikipedia section was doing, by the way).

According to Aaron Spitz, a urologist, many websites and studies promoting variation of penis size between races use unscientific methods of collecting information and often ignore contradictory evidence. He concludes that “when you really take a good look at the naked data, there’s not a whole lot there [showing racial variation in penis size].”[34]

Unfortunately this dude made this claim in a book, which I don’t feel like buying and reading. And he’s not wrong – as far as I can tell we haven’t had a good, high-n study that was careful to use the same measuring techniques across races.

There are some other studies that do suggest penis size correlations with length, though a lot are self reports. This page from suspiciously-named penissizes.org claims to have gone through a bunch of studies and found correlations between penis size and race, but they don’t give a lot of info about their methodology and also say “we need to do more research.”


So I can’t say Wikipedia is wrong – according to the sources it gave, there’s no good evidence to support racial correlation with penis size, but there’s also not good evidence to say there isn’t any, either. And over and over again, I find articles online quoting the sources above to conclude that there isn’t any correlation. It’s like, if a few meta analyses found “Hey, we haven’t done the research required to determine if there’s a correlation between hand size and longevity yet,” and then everybody ran around reporting “There’s no correlation between hand size and longevity, it’s a myth!” No, jesus, we just haven’t figured it out yet.

(I also didn’t look deeply into arguments claiming that there is a correlation; it’s possible there’s some solid evidence out there in the other direction).

But race is correlated with height, and height is correlated with penis size, so thus, race should be correlated with penis size. If this isn’t the case, and it might not be, it’d be super interesting to know, and I’d love to see research about it. It’d be a much more fascinating reality than if there were a race-penis size correlation; why would smaller men have proportionately larger penises??

13 thoughts on “Is penis size and race really uncorrelated?

  1. “But even if we take the Wikipedia summary at face value, then is it claiming that Tanzanian men have smaller penises than average? Wouldn’t this be dangerously close to suggesting there’s some racial correlation with penis size anyway?”
    No, it does not. Nationality is not race, and correlation is not causation.

    Malnutrition has a lot more to do with height of people and penis length than any other factor. For example, malnutrition can severely delay and stunt puberty resulting in permanent effects even in adulthood and beyond.

    For example, Dutch people went from being among the shortest people (due to malnutrition) to being the tallest people because of more access to food (and access to healthier food). For the same reason, Iranian men are the fastest growing group of people on the planet in terms of average height increase.

    They should do a study to compare black men living in France for example, to men from their country of origin in Africa. (so Nigerians living in France, compared to Nigerians living in Nigeria).

    You can’t really study people from different ethnicities like that when nutrition and health is such a huge variable between countries (and regions within countries). Of course there will be some differences between ethnicities (for example, average penis size in Congo is WAY above everyone else) but it’s not easy to compare different groups when they’re not on an even playing field in terms of poverty and malnutrition, so the margin of error will be huge and you will end up attributing differences caused by malnutrition to “race”.

    There’s also the fact that there is no unified “black race” or “white race” or “asian race” as there are many differences between ethnicities that otherwise get grouped together.

  2. Note that correlation isn’t necessarily transitive, if X correlates positively with Y and Y positively with Z, then it is possible with X and Z to be negatively correlated.

  3. Great post. Is the raw data available anywhere? It shouldn’t be a difficult problem if data sets are available. You would hope the set contained candidates with all columns filled per person, i.e. a study that traced race, height and penis size in the same set for person X. But if not, correlations between means of sets may show something. Do any of these studies show methodology/reveal data sets?

  4. Because it has so many small and extremely isolated ethnic groups, Africa has more human genetic diversity than any other continent. I imagine there’s *huge* variation across the continent. Two studies with n<1000 that only look at Tanzania and Nigeria hardly cut the surface on the amount of data collection needed to even speak to this. Bad Wikipedia. Go to your room.

  5. Am I the only one concerned that in all of the quoted numbers the “stretched” average length is longer than the erect average length?

    For the love of god, how hard are they stretching?

    Or if the data are correct, does this mean nearly all men are “showers” (i.e. flaccid and erect length are similar) rather than “growers” (erect length longer than flaccid) so much so that “growers” do not show up in the average data?

    Both of these confound all of my expectations.

  6. The paper you linked for “correlation for penis length with height” seems to be very weak. There was only one study that found strong correlation (0.6), 4 studies that for weak correlations (0.2-0.3) and 2 studies that found no correlation. Then how can you say the the height is correlated with penis size?

    P.S: I am asking you this because your argument for race correlation with penis size is in the line of, correlation of height with race and correlation of height with penis length, therefore correlation of penis length with race.

  7. I’m pretty surprised that there isn’t some 19th-century racial science investigation of this. Weren’t they all deeply into body measurements?

  8. Hello, random guy here. I’m wondering how much epigenetics have to play. From things like diet to activity level, and even factors such as illnesses and amount of male vs female interaction during certain key times in development, etc. – all these could turn genes on and off that effect size.

    It is definitely true some genetically similar groups have a higher propensity for larger penises, and thats true for folks of many “races”. Some of these folks will then express those genes more strongly than others within that group due to the epigenetics mentioned above.

    So, I think it’s way more complex biologically. And as far as anecdotal accounts, I posit that most of the “black” penises most of us have ever seen are probably on the largest end of the spectrum, as that has become the standard within porn, and amateurs probably self select for his feature.

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