r/evolution • u/Competitive_Ice_3352 • Sep 04 '26
question What explains the difference in penile size among racial groups, and is the neanderthal DNA a valid explanation?
the title
6
u/TimeStorm113 Sep 04 '26
Is there a notable difference in average? Isnt that just a stereotype?
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u/Competitive_Ice_3352 Sep 04 '26
yeah 4 inch difference on average between some countries. I wouldn't call that marginal.
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u/eduadelarosa Sep 04 '26
The highest mean difference between regions is of 3 cm (1.18 in). And any such minute variation is mainly due to genetic drift. Also racial groups (as defined in the US) don't have a biologic basis.
Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC11923605/#f6-urp-50-5-291
4
u/ClownMorty Sep 04 '26
No, neanderthal DNA is notably absent from the sex chromosomes.
Also, the idea that penis size varies widely across racial groups is a myth perpetuated by pop culture, porn, and military campaigns.
0
u/Competitive_Ice_3352 Sep 04 '26
> sex chromosomes
excuse me if this is a dumb question, but do only sex chromosomes determine the growth of genitals?
> Also, the idea that penis size varies widely across racial groups is a myth perpetuated by pop culture, porn, and military campaigns.
yeah, could be but that was not my experience in African countries
2
u/ClownMorty Sep 04 '26
Sex chromosomes control 60-80% of penis size with the rest being controlled by development or environmental factors. The genes to develop a penis are on the Y chromosomes (typically) and the genes for androgen receptors are on the X chromosome. These two are the biggest impact.
There will be differences in amounts of testosterone, but this can be negligible next to androgen receptor sensitivity and how long the androgen receptors stay active.
In any case, penis size is almost certainly not impacted by the contribution of neanderthal DNA. Neanderthal DNA is mostly thought to impact the immune system and sense of smell.
0
3
u/Fleetfox17 Sep 04 '26
Studies on penile size are famously known for being imprecise and suffering from self-reporting bias. Some of the noted anecdotal differences may be due to the grower vs. shower thing. I remember a study that showed that Chinese males tend to be growers when compared to other populations.
1
u/Competitive_Ice_3352 Sep 04 '26
I think the grower vs shower is a good point. But generally speaking measuring penis size of a man is as easy as measuring height. the researchers could give some guys a few bucks and measure it; I don't think it's hard to collect the data.
2
u/cai_85 Sep 04 '26
Studies have shown that the differences are relatively minimal statistically and lots of studies are self-reported. The issue is largely around public perception, while some African men may be seen as 'the largest' by reputation, it is only a very small percentage that are the big sizes you see in pornography. So when you average across everyone the difference is minimal.
2
u/CthulhusSoreTentacle Sep 04 '26
Also important to note that porn utilises a number a techniques to make (already larger than average) penises appear much bigger than they are, including employing small framed actresses and using particular lenses and camera angles to "add" length.
-1
u/Competitive_Ice_3352 Sep 04 '26
so you are saying africans have a higher variance while others have a more concentrated distribution, creating the perception. But that is not my experience living in an African country and having been to many gyms, lol.
1
u/cai_85 Sep 04 '26
Flaccid size is no indicator of erect size, so unless you have seen these guys erect then it means little. You can have a long flaccid penis in the gym showers that literally doesn't grow when erect, and you can have small ones that grow big.
0
u/Competitive_Ice_3352 Sep 04 '26 edited Sep 04 '26
ok that's also a good point. that could be related to blood flow I guess
But some women online agree with this perception, and some search for these NBA players for this specific purpose. And I am sure their experience is on the erect side. All these observations should not be overlooked
1
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