Is Large Penis Size a Recent Evolutionary Change?

[deleted356736]

Apparently, you don't know much about anything.

I am a qualified accountant, a CPA and a qualified psychologist. I can't mess with your head, but I sure know a lot more than a nobody like yourself.

The average chimp's penis is a little over 3 inches (approx. 8 cm) in length. It is very slender even at the base, and it tapers to a point, as it lacks a swollen "head" at the end. That's smaller than my middle finger. Chimps are able to "show off" with such a meagre organ because it is a bright pink color that contrasts with their black fur. Their manner of achieving penile erection is also different from that of humans.

In summary, chimps exhibit smaller penes, larger testes, and a higher degree of female promiscuity (polyandry) than humans. Thus, theory-based claims of a direct correlation between female promiscuity and male penis size or between testis size and penis size are not supported by empirical evidence in interspecies comparison between humans and the nearest extant taxon.

I quoted I'm not a biologist, so good for you that you can misquote facts on primates. But I am a psychologst who did a thesis on human sex as part of my studies, and those studies were much more valuable to my life than an advanced knowledge of chimps! I believe an ape, which is many times the physical size of a chimp, has a penis about half the size (1.5" erect length). So, it seems, by primate standards the chimp is both promiscuous and well-hung.

 

[D_Jimmy Jammer]

I am a qualified accountant, a CPA and a qualified psychologist.

I'm unsure, cbrmale, of the value, in this context (LPSG), of accountancy and the CPA (Cert Public Accountant?) - do tell, if you've found good use for it - but, yes, the psych qual could be handy. :tongue:

 

[D_Jimmy Jammer]

when humans began to stand upright, they began having sex facing each other. Because of the position of the vagina only longer penises could penetrate deep enough to have a good chance at reproduction. Through natural selection the smaller penises kept getting weeded out until pretty much all remaining genes were those of larger penises being passed down. They have continued to get larger until now and I'm sure they will continue in the future.

Sounds shallow. I'd have thought humans would more easily adapt their position rather than males the length of the penis. Much easier. In terms of time, what would it take - a day or two, a week, a month? As a matter of fact, I have a long dick but my natural inclination, from the year dot, was to lay my partner on her back..not stand her up. I have had 'vertical' sex, but it's never been as satisfying. Generally, how popular is that position?
There's another species survival point: wouldn't gravity (standing upright while copulating) potentially, adversely affect conception? Ah, long cock evolutionists will no doubt argue, 'the very reason they've lengthened, to place sperm close to the cervical os..'
Pull the other one. :biggrin1:

 

[bigirishman]

well one reaason we mayhave evolved so quickly ove past 10 thoushand years is after last glaciation humanity has devided into several races and traveled greatly into different environments and become socially comples thus the range of geneics required for one ot fill each niche in the society is great.
Mabie one explenationof the increased penis size si due to the fact that we are standing on two legs compared to the other primates.
Other priates mound during sex from behind.
Since standing upright we have moved to front. the vagina moving more towards front and the developemenat of permanent large breasts to attract men to the front where the sexual position is more sucessfull also followed. Mabie the development of a larger penis also evolved with these changes so as to accomidate these changes.
and then mabie selective breedign on the womans behalf in favour of a larger penis could habe been in play. we know that men withing goups with larger penises will obtain haigher ranking status. More social power and thus will be more likely to sucessfully inseminate a feamle. Also larger penis and testicles are associated with higher testosterone levels thus stronger men.

The question will humans penises continue to become bigger well that all depends if penis size is a deciding factor in the insemination of females. Do men with larger pesises tend to impregnate more wemon? Is this statistically significant to the point that it allows for a reduced impregnation rate by small penis men?
Well i think men with larger penises tend to get more sex are more confident and sucessfull so there will probable (IN my openion based on no research or evidence) be a increase in penis size over time if it becomes and or remains a deciding factor in the choice of a sexual partner for women.
Which i think it is

One fact not mentioned is that our bodies are getting closer to reaching their genetic potential in many aspects such as build height, intelligance ets as we are more nutritionally aware and malnutriton is reduced

Thats my swing on things anyway
BTW i am a scientist and have particular interest in behavoral ecolagy human behaviour and realated subjects. would be interesting piece of research to take up
Later
bigirishman

 

[D_Jimmy Jammer]

Lots of conjecture there, bigirish..

..mabie selective breedign on the womans behalf in favour of a larger penis could habe been in play. we know that men withing goups with larger penises will obtain haigher ranking status. More social power and thus will be more likely to sucessfully inseminate a feamle. Also larger penis and testicles are associated with higher testosterone levels thus stronger men.

If you are a behavioural, ecological (ethnological?), and related (endrocrinological?) scientist you should be aware that even if females did choose males with a large penis, current thinking argues offspring penis-size seems more related to female genes than male genes (you'll have to do your own reading..) Higher testosterone levels are more likely associated with healthy (not larger) testicles and, to a lesser extent, healthy adrenals. However, there is also a raging 'chicken and egg' debate around behaviour affecting testosterone levels..testosterone levels affecting behaviour.
Here's an interesting current reference for you -
Endocrinology of Social Relationships, ed. Ellison and Gray, 2010.
:tongue:

 

[jujube]

The penis size that an individual ends up with as an adult has nothing to do with testosterone; if it did, men should be able to increase the size of their penes by taking testosterone supplements, and I think everyone should have realized by now that that does not work. The sudden increase in serum testosterone levels associated with the onset of puberty in males merely acts as a catalyst (or a trigger, if you will) for the genitalia to develop to their adult size. An individual's maximum size must be predetermined by genes, or else the organ should continue to grow as long as it is exposed to testosterone, which continues to be produced throughout a man's adult life. Supplementing or reducing serum testosterone in a post-pubertal male has no effect on penis size, though supplementing testosterone in a pre-pubertal male will induce puberty (or at least some aspects of it) prematurely.

 

[deleted356736]

The penis size that an individual ends up with as an adult has nothing to do with testosterone; if it did, men should be able to increase the size of their penes by taking testosterone supplements, and I think everyone should have realized by now that that does not work. The sudden increase in serum testosterone levels associated with the onset of puberty in males merely acts as a catalyst (or a trigger, if you will) for the genitalia to develop to their adult size. An individual's maximum size must be predetermined by genes, or else the organ should continue to grow as long as it is exposed to testosterone, which continues to be produced throughout a man's adult life. Supplementing or reducing serum testosterone in a post-pubertal male has no effect on penis size, though supplementing testosterone in a pre-pubertal male will induce puberty (or at least some aspects of it) prematurely.

Unsubstantiated speculation. It's actually theorised that the mother's level of testosterone while she is carry a male foetus is the trigger for large penis size, although the reason for this variability is unknown.

As an aside, women who are pregnant with baby boys are often instatiably horny throughout pregnancy (that testosterone at work).

 

[ZachMorris]

This thread is quite humorous. Pondering penis evolution. I will have to submit it to NOVA.

 

[jujube]

As an aside, women who are pregnant with baby boys are often instatiably horny throughout pregnancy (that testosterone at work).

I have a hard time accepting claims from an ignoramus who does not even know how to spell "insatiably" unless he supports his claims with convincing scientific evidence from a third party.

STEROID HORMONES.
During pregnancy, there is a gradual increase in the urinary excretion of progestins and estrogens. This change in steroid metabolism with gestation is secondary to the biosynthesis of steroid hormones by the placenta and fetus.
Three estrogens are produced by the placenta: estrone, 17β-estradiol, and estriol (Fig. 13). The primary evidence for their production by the placenta is the fact that placental fragments incubated in vitro synthesize estrogens from neutral C-19 steroids. The fetus and placenta must be present for the production of the large amounts of maternal estrogen normally found in serum and urine during pregnancy; thus, the term fetoplacental unit was coined. The placenta aromatizes the androgens dehydroepiandrosterone, androstenedione, and testosterone, produced by the fetus, to estrogens. This process takes place in the placental microsomes and is catalyzed by cytochrome P-450. The synthesis of estrogen is known to be stimulated by hCG and hPL, and the placenta may regulate its own estrogen synthesis.

If the androgens produced by a male fetus, such as testosterone, have any effect on maternal libido, it seems that it should be through an additional increase in the mother's estrogen levels over and above the increase that results from the synthesis of estrogen in the placenta during gestation of any fetus regardless of its sex.

Can you produce any evidence that would suggest that fetally produced testosterone can be carried across the maternal-placental blood barrier in amounts significant enough to affect the behavior of a pregnant human female without being converted into estrogen through the activity of placental aromatase?

Furthermore, please consider the results of a study (R. Troisi et al. 2008) in which the researchers have analyzed the concentrations of various hormones in sera obtained from PRC Chinese and US white newborn infants' umbilical cords (which are, of course, part of the fetal-placental unit rather than part of the mother) in an attempt to test the hypothesis that the low rate of breast cancer that has been observed in East Asian women is due to prenatal differences rather than to established adult risk factors:

In conclusion, we found higher concentrations of estriol, androstenedione, testosterone, and IGFBP-3 and lower prolactin in cord serum from Chinese compared with U.S. neonates, whereas levels of estradiol and IGF-I were not different. These data are consistent with the hypothesis that elevated prenatal androgen exposure may be protective against subsequent breast carcinogenesis. Whereas the focus of this paper is on breast cancer, these results may be relevant for other endocrine cancers that have been suggested as being associated with fetal hormone exposure, including testicular and prostate cancer.

In other words, the concentration of androgens in the blood of the umbilical cords of neonatal Chinese infants has been found to be significantly higher than the concentration of androgens in the blood of the umbilical cords of neonatal American white infants. I have no desire to perpetuate certain well-known stereotypes on this forum, but please be aware that if you want to argue that variance in a fetus' level of exposure to testosterone (or androgens in general) is the primary (or even the only) cause of variance in adult penis size, this study's results suggest that you should be assuming that Chinese males have significantly larger penes than American white males.

 

[Sergeant_Torpedo]

It is like the rules regulating height, just the same basically. Well nourished individuals will within predisposed gene pools increase their height over several generations but eventually it will max out and the phenomenon of a tall guy's son's being shorter than he. Same with penises. If great great grandfather had a monster in his breeches chances are yours will be average.

 

[jujube]

It is like the rules regulating height, just the same basically. Well nourished individuals will within predisposed gene pools increase their height over several generations but eventually it will max out and the phenomenon of a tall guy's son's being shorter than he. Same with penises. If great great grandfather had a monster in his breeches chances are yours will be average.

Please produce some evidence to support your hypothesis.

I will note here in passing that final adult height is not increased by androgen exposure. On the contrary, it is a well-documented fact that human males who have been castrated prior to puberty grow to much greater than average height almost without exception; this suggests that the androgen exposure that triggers puberty in a human male actually decreases the individual's final adult height, as higher levels of testosterone ultimately are converted into higher levels of estradiol, an estrogen which accelerates bone maturation and thus prevents further growth. The difference in average height between normal adult human males and normal adult human females must be caused by a gene or genes located on the Y-chromosome, which is carried only by males, or on the X-chromosome, which is carried by both males and females, but with an extra copy in the latter (although certain genes supposedly are activated only on one copy of the X-chromosome in females).

 

[deleted356736]

The penis size that an individual ends up with as an adult has nothing to do with testosterone; if it did, men should be able to increase the size of their penes by taking testosterone supplements, and I think everyone should have realized by now that that does not work. The sudden increase in serum testosterone levels associated with the onset of puberty in males merely acts as a catalyst (or a trigger, if you will) for the genitalia to develop to their adult size. An individual's maximum size must be predetermined by genes, or else the organ should continue to grow as long as it is exposed to testosterone, which continues to be produced throughout a man's adult life. Supplementing or reducing serum testosterone in a post-pubertal male has no effect on penis size, though supplementing testosterone in a pre-pubertal male will induce puberty (or at least some aspects of it) prematurely.

Produce your peer-reviewed scientific evidence to subbort this rubbish, please.

 

[deleted356736]

Please produce some evidence to support your hypothesis.

I will note here in passing that final adult height is not increased by androgen exposure. On the contrary, it is a well-documented fact that human males who have been castrated prior to puberty grow to much greater than average height almost without exception; this suggests that the androgen exposure that triggers puberty in a human male actually decreases the individual's final adult height, as higher levels of testosterone ultimately are converted into higher levels of estradiol, an estrogen which accelerates bone maturation and thus prevents further growth. The difference in average height between normal adult human males and normal adult human females must be caused by a gene or genes located on the Y-chromosome, which is carried only by males, or on the X-chromosome, which is carried by both males and females, but with an extra copy in the latter (although certain genes supposedly are activated only on one copy of the X-chromosome in females).

It's actually theorised that men who have higher levels of adolescent testosterone pass into puberty at a younger age, which means they complete their adolescent growth spurt at a younger age as well. That is, they are shorter with bigger dicks. Women, who generally commence puberty at an earlier age than men, also generally end up shorter than the average man. You're over-analysing it.

 

[B_625girth]

define "recent". I watched a show on TV where they speculated that we are slowly constantly evolving, and that penis size increased because those with a big penis had more sex and therefore more children, passing down their attributes than those men who are smaller cocks. I won't live long enuf to tell, so I'll just enjoy the big cock I was given.

 

[deleted356736]

define "recent". I watched a show on TV where they speculated that we are slowly constantly evolving, and that penis size increased because those with a big penis had more sex and therefore more children, passing down their attributes than those men who are smaller cocks. I won't live long enuf to tell, so I'll just enjoy the big cock I was given.

Evolution seems to happen faster than originally theorised. There are certain traits that define a person as being attractive, and it's been discovered that over the last 100 years or so, women have become more attractive at an almost astonishing rate. To test this, go and look at photos taken in the early days of photography, and compare those photos with average women today. Men, on the other hand, haven't become more attractive.

Another example is in Africa, where men preferred their women to be stout and good survival material in a harsh and drought-ravished continent. But then Africa gets pictorial exposure to the European style of attractive: tall, slim, long-legged and - voila - the latest generation of African women are taller, slimmer and longer-legged than before. And this is despite a relatively poor diet that hasn't changed much over the past fifty years or so.

 

[Cobalt Blue]

Possibly the most compelling thread ever on LPSG. Excellent stuff, please keep posting...

 

[D_Jimmy Jammer]

But then Africa gets pictorial exposure to the European style of attractive: tall, slim, long-legged and - voila - the latest generation of African women are taller, slimmer and longer-legged than before. And this is despite a relatively poor diet that hasn't changed much over the past fifty years or so.

I suspect that could only happen, as quickly as you suggest, through cross-breeding/mixing of tribes, one of which is tall and has long-limbed physiology, i.e. genetics. Diet can produce quite quick and dramatic change. Conspicuous inter-generational increases in the height (lean and tall) of (not all) Japanese males occured rapidly after WWII between, particularly, the 1950s-1960s and the 1970s-1980s (high protein, reduction in carbs, animal and vegetable fat intake.) It's ongoing. More recently, however, there's an emerging, worrying, 'big and fat' (obesity) cohort attributed to sedentary life-style and marked by high cholestrol - both kids and adults.
But you say diet has remained poor in Africa.

 

[B_quietguy]

I came across this quote on the wide variety of cock sizes and shapes. It makes the point that evolution will favor more diversity among cock sizes and shapes than among other organs.

"Considering the fact that the cock is the most critical link in our chain of survival, the variety of shapes, colors, sizes, characteristics, dispositions and responses found in this rudimentary tool are much greater than those shown in any other organ of the body. They were black, white, red, yellow, lavender, brown, warty, wrinkled, comely and silken, and they seemed, any like crowd of men on a street at closing time, to represent youth, age, victory, disaster, laughter and tears." - from "Falconer" by John Cheever (1975)

 

[D_Harry_Crax]

Jason, you present some intriguing ideas, but is there any proof that people in warmer climates have longer flaccid cocks?

Jason, yes, Indian men live in a hot climate and generally tend to have small cocks, erect and flaccid.

 

[D_Jimmy Jammer]

Indian men live in a hot climate and generally tend to have small cocks, erect and flaccid.

Big generalization. Not from what I've seen