Saturday, June 6, 2015

How big is the average penis?

New data let men take a closer look at how they stack up.
ANDREY POPOV/SHUTTERSTOCK
New data let men take a closer look at how they stack up.

How big is the average penis?

“I was in the pool!” George Costanza’s distress at the “shrinkage” of his penis after exiting a cold pool was hilarious in the 1994 Seinfeldepisode, but for many men concern over the length and girth of their reproductive organ is no laughing matter. Now, a new study could assuage such worries with what may be the most accurate penis-size measurements to date.
Many earlier studies relied on self-reporting, which doesn’t always yield reliable results. “People tend to overestimate themselves,” says David Veale, a psychiatrist at the South London and Maudsley NHS Foundation Trust. So when Veale and his team set out to settle the score on penile proportions, they decided to compile data from clinicians who followed a standardized measuring procedure.
Published today in the British Journal of Urology Internationaltheir new study synthesizes data from 17 previous academic papers that included measurements from a total of 15,521 men from around the world. The data enabled the researchers to calculate averages and model the estimated distribution of penile dimensions across humanity. “It still just strikes me how many men have questions and insecurities and concerns about their own penis size. We actually do need good data on it,” says Debra Herbenick, a behavioral scientist at Indiana University, Bloomington, who was not involved in the study.
According to the team’s analysis, the average flaccid, pendulous penis is 9.16 cm (3.61 inches) in length; the average erect penis is 13.12 cm (5.16 inches) long. The corresponding girth measurements are 9.31 cm (3.66 inches) for a flaccid penis and 11.66 cm (4.59 inches) for an erect one.
A graph of the size distribution shows that outliers are rare. A 16-cm (6.3-inch) erect penis falls into the 95th percentile: Out of 100 men, only five would have a penis larger than 16 cm. Conversely, an erect penis measuring 10 cm (3.94 inches) falls into the 5th percentile: Only five out of 100 men would have a penis smaller than 10 cm.
Gentlemen, if you’re eager to see how you measure up, you’ll need to follow the same measurement procedure used in the study. All length measurements were made from the pubic bone to the tip of the glans on the top side of the penis. Any fat covering the pubic bone was compressed before measurement, and any additional length provided by foreskin was not counted. Circumference was measured at the base of the penis or around the middle of the shaft, as the two sites were deemed equivalent.
The researchers concluded that there was no strong evidence to link penis size to other physical features such as height, body mass index, or even shoe size. Yes, it seems that the only definite conclusion that can be drawn about a fellow with big socks is that he probably has big feet. Likewise, the study found no significant correlation between genital dimensions and race or ethnicity, although Veale points out that their study was not designed to probe such associations, because much of the data used were from studies of Caucasian men.
It’s easy to laugh at poor George Costanza for his shrunken manhood, but some reports suggest that only about 55% of men are satisfied with their penis size. Some seek potentially dangerous surgical solutions to a problem that, according to Veale, is often only in their head. Men “seem to have a very distorted picture of what [size] other men are, and what they believe they should be,” Veale says.
Pornography, in which male performers are often selected for their extremely large genitalia, may be partly to blame. Similarly, Herbenick points to the myriad spam e-mails that assert that 17.78 cm (7 inches) is average for an erection, when in reality such a member would place its owner in about the 98th percentile. It’s best to just ignore those ads in any case, Veale says. “There are no effective lotions or potions or pills.”
Posted in Biology
Science| DOI: 10.1126/science.aaa7934
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Human penis size

Human penis size
From Wikipedia, the free encyclopedia
"Penis length" redirects here. For differences in penis length among non-human species, see Penis § In different animals.

Showing how to measure length and circumference of penis


Average penis size revealed in study results

International study of 15,000 penises is being used to reassure men concerned they are not within the ‘normal range’

measuring tape
 In a flaccid state, the penis of the average man is 9.16cm (3.6 inches) in length. Photograph: Alamy

The enduring question now has a scientific answer: 13.12 centimetres (5.16 inches) in length when erect, and 11.66cm (4.6 inches) around, according to an analysis of more than 15,000 penises around the world.
In a flaccid state, it found, the penis of the average man is 9.16cm (3.6 inches) in length and has a girth of 9.31cm (3.7 inches).


The numbers should help “reassure the large majority of men that the size of their penis is in the normal range”, said British researchers who had assembled data from studies where participants had their member measured by a professional.
The team then used the collated numbers to devise a graph that doctors can use in counselling men with “small penis anxiety”.


penis size graph
 Graph for flaccid, flaccid stretched and erect length of the penis. Illustration: Veale et al. 2014

In the worst cases, men may be diagnosed with body dysmorphic disorder – a debilitating psychological condition that can lead to obsessive and anti-social behaviour, depression and even suicide.
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In reality, only 2.28% of the male population have an abnormally small penis, said the study – and the same percentage an unusually large one.
The study participants were men aged 17 to 91 who had their penises measured in 20 previously published studies conducted in Europe, Asia, Africa and the United States.
The team found no evidence for penis size differences linked to race, though most of the study participants were of European and Middle Eastern descent and a full comparison could thus not be made.
Nor did the researchers find any convincing correlation between a man’s foot size and the length of his manhood.
They acknowledged their results may have been somewhat skewed by the possibility that men who volunteer to be examined may be more confident in their penis size than the general population.
The team said their work, published in the BJU International journal of urology, was the first to combine all existing data on penis length and girth into a definitive graph.
The information may be useful for reassuring men worried about their size. But it may also have the unintended effect of denting the egos of those who thought they were abnormally well-endowed.
Doctors may also use the graph t
The most accurate measurement of the human penis comes from several measurements at different times since there is natural minor variability in size due to arousal level, time of day, room temperature, frequency of sexual activity, and reliability of measurement. When compared to other primates, including large primates such as the gorilla, the human penis is largest, both in absolute terms and relative to the rest of the body.

Measurements vary, with studies that rely on self-measurement reporting a significantly higher average than those with staff measuring. As of 2015, a systematic review of the best research to date on the topic has concluded that the mean length of an erect human penis is approximately 13.12 ± 1.66 cm (5.17 ± 0.65 in).[1] Flaccid penis length is a poor estimate of erect length.

Most of human penis growth happens between infancy and the age of five, and between about one year after the onset of puberty and, at latest, approximately 17 years of age.[2]systematic review of the best research to date on the topic has concluded that the mean length of an erect human penis is approximately 13.12 ± 1.66 cm (5.17 ± 0.65 in).[1] Flaccid penis length is a poor estimate of erect length.

Most of human penis growth happens between infancy and the age of five, and between about one year after the onset of puberty and, at latest, approximately 17 years of age.[2]

A statistically significant correlation between penis size and the size of other body parts has not been found in research. Some environmental factors in addition to genetic, such as the presence of endocrine disruptors, can affect penis growth. An adult penis with an erect length of less than 7 cm (just under 3 inches), but otherwise formed normally, is referred to in medicine as a micropenis.

Contents  [hide]
1 History
2 Studies on penis size
2.1 Length
2.1.1 Flaccid length
2.1.2 Stretched length
2.1.3 Erect length
2.2 Erect circumference
2.3 Size at birth
2.4 Size with aging
3 Variance in penis size
3.1 Micropenis
3.2 Environmental influence on penis size
4 Perceptions of penis size
4.1 Historical perceptions
4.2 Male self-perception
4.2.1 Among gay men
4.2.2 Anxiety about penis size
4.3 Penis size and size of other body parts
5 Studies of size preferences among sexual partners
6 Evolution
7 Penis size and condom use
8 See also
9 References
History
Perceptions of penis size are culture-specific. In Ancient Greece and in Renaissance art, an uncircumcised and small penis was culturally seen as desirable in a man, whereas a bigger or circumcised penis was viewed as comical or grotesque. Ancient Rome may have had a contrary view, and a larger penis size was preferred in medieval Arabic literature.[citation needed] Males may quite easily underestimate the size of their own penis relative to that of others, and many men who believe that their penis is of inadequate size have average-sized penises. The perception of having a large penis is often linked to higher self-esteem.[3] Fears of shrinking of the penis in folklore have led to a type of mass hysteria called penis panic, though the penis legitimately can shrink in size due to scar tissue formation in the penis from a medical condition called Peyronie's disease.[4][5] Marketers of penis enlargement products exploit fears of inadequacy, but there is no consensus in the scientific community of any non-surgical technique that permanently increases either the thickness or length of the erect penis that already falls into the normal range.

Studies on penis size
While results vary slightly across reputable studies, the consensus is that the mean human penis is in the range 12.9–15 cm (5.1–5.9 in) in length with a 95% confidence interval of (10.7 cm, 19.1 cm) or, equivalently (4.23 in, 7.53 in) — that is, it is 95% certain that the true mean is at least 10.7 cm but not more than 19.1 cm.[6][7][8]

A 2015 systematic review published by Veale et.al. of medical research on the topic over the previous 30 years published in BJU International showed similar results, giving mean flaccid, stretched non-erect, and erect lengths of 9.16 cm, 13.24 cm, and 13.2 cm respectively, and mean flaccid and erect circumferences of 9.31 cm and 11.66 cm respectively.[1]

Length
Flaccid length
One study found the mean flaccid penis length to be 3.5 inches (8.9 cm) (measured by staff).[6] A review of several studies found average flaccid length to be 9–10 cm (3.5–3.9 in).[9] Length of the flaccid penis does not necessarily correspond to length of the erect penis; some smaller flaccid penises grow much longer, while some larger flaccid penises grow comparatively less.[10]

The penis and scrotum can contract involuntarily in reaction to cold temperatures or nervousness, referred to by the slang term "shrinkage", due to action by the cremaster muscle. The same phenomenon affects cyclist and exercise bike users, with prolonged pressure on the perineum from the bicycle saddle and the straining of the exercise causing the penis and scrotum to contract involuntarily. An incorrect saddle may ultimately cause erectile dysfunction (see crotch pressure for more information).

Stretched length
Neither age nor size of the flaccid penis accurately predicted erectile length. Stretched length most closely correlated with erect length.[6]

Erect length
Several scientific studies have been performed on the erect length of the adult penis. Studies which have relied on self-measurement, including those from Internet surveys, consistently reported a higher average length than those which used medical or scientific methods to obtain measurements.[8][11]

The following staff-measured studies are each composed of different subgroups of the human population (i.e. specific age range and/or race; selection of those with sexual medical concerns or self-selection) which could cause a sample bias.[11][12]

In a study of eighty healthy males published in the September 1996 Journal of Urology an average erect penis length of 12.9 cm (5.1 in) was measured.[6] The purpose of the study was to "provide guidelines of penile length and circumference to assist in counseling patients considering penile augmentation." Erection was pharmacologically induced in 80 physically normal American men (varying ethnicity, average age 54). It was concluded: "Neither patient age nor size of the flaccid penis accurately predicted erectile length."
A study published in the December 2000 International Journal of Impotence Research found that average erect penis length in 50 Jewish Caucasian males was 13.6 cm (5.4 in) (measured by staff).[7] Quote: "The aim of this prospective study was to identify clinical and engineering parameters of the flaccid penis for prediction of penile size during erection." Erection was pharmacologically induced in 50 Jewish Caucasian patients who had been evaluated for erectile dysfunction (average age 47±14y). Patients with penis abnormalities or whose ED could be attributed to more than one psychological origin were omitted from the study.
A review published in the 2007 issue of BJU International showed the average erect penis length to be 14–16 cm (5.5–6.3 in) and girth to be 12–13 cm (4.7–5.1 in). The paper compared results of twelve studies conducted on different populations in several countries. Various methods of measurements were included in the review.[9]
An Italian study of about 3,300 men concluded that stretched length was measured on average to about 12.5 centimetres (4.9 in). In addition, they also checked for correlations in a random subset of the sample consisting of 325 men. They found a few statistically significant Spearman's correlations: between flaccid length and height of 0.208, −0.140 with weight, and −0.238 with BMI, flaccid circumference and height 0.156, stretched length and height 0.221, weight −0.136, BMI −0.169. They also reported a few non-significant correlations.[13]
Erect circumference
Similar results exist regarding studies of the circumference of the adult fully erect penis, with the measurement taken mid-shaft.[citation needed] As with length, studies that relied on self-measurement consistently reported a significantly higher average than those with staff measuring. In a study of penis size where measurements were taken in a laboratory setting, the average penis circumference when erect was 4.8 inches (12.3 cm), which means that the average width of the erect penis is approximately 1.5 inches (4 cm).[14][15]

Size at birth
The average stretched penile length at birth is about 4 cm (1.6 in), and 90% of newborn boys will be between 2.4 and 5.5 cm (0.94 and 2.17 in). Limited growth of the penis occurs between birth and 5 years of age, but very little occurs between 5 years and the onset of puberty. The average size at the beginning of puberty is 6 cm (2.4 in) with adult size reached about 5 years later. W.A. Schonfeld published a penis growth curve in 1943.[16]

Size with aging
Authors of a paper reviewing research on area of penis sizes conclude that "flaccid penile length is just under 4 cm (1.6 in) at birth and changes very little until puberty, when there is marked growth."[2][9]

Age is not believed to negatively correlate with penis size. "Individual research studies have... suggested that penis size is smaller in studies focusing on older men, but Wylie and Eardley found no overall differences when they collated the results of various studies [over a 60 year period],"[9] however, there is some evidence to suggest that testicle size is getting progressively smaller with younger cohorts.[17]

Variance in penis size
Micropenis
Main article: Micropenis
An adult penis with an erect length of less than 7 cm or 2.76 inches but otherwise formed normally is referred to in a medical context as having the micropenis condition.[18] The condition affects 0.6% of men.[10] Some of the identifiable causes are deficiency of pituitary growth hormone and/or gonadotropins, mild degrees of androgen insensitivity, a variety of genetic syndromes, and variations in certain homeobox genes. Some types of micropenis can be addressed with growth hormone or testosterone treatment in early childhood. Operations are also available to increase penis size in cases of micropenis in adults.[19]


Measuring erect micropenis
Environmental influence on penis size
It has been suggested that differences in penis size between individuals are caused not only by genetics, but also by environmental factors such as culture, diet, and chemical or pollution exposure.[20][21][22][23] Endocrine disruption resulting from chemical exposure has been linked to genital deformation in both sexes (among many other problems). Chemicals from both synthetic (e.g., pesticides, anti-bacterial triclosan, plasticizers for plastics) and natural (e.g., chemicals found in tea tree oil and lavender oil)[24][25] sources have been linked to various degrees of endocrine disruption. Both PCBs and the plasticizer DEHP have been associated with smaller penis size.[26] DEHP metabolites measured from the urine of pregnant women have been significantly associated with the decreased penis width, shorter anogenital distance, and the incomplete descent of testicles of their newborn sons, replicating effects identified in animals.[27] Approximately 25% of US women have phthalate levels similar to those in the study.[27] A 2007 study by University of Ankara, Faculty of Medicine found that penile size may decrease as a result of some hormonal therapy combined with external beam radiation therapy.[28] In addition, some estrogen-based fertility drugs like diethylstilbestrol (DES) have been linked to genital abnormalities and/or a smaller than normal penis (microphallus).[29]

Perceptions of penis size
Historical perceptions

Fresco of Priapus from Pompeii. Depicted weighing his large erect penis against a bag of gold. Ancient Romans admired the large penis of Priapus.[30]
According to Kenneth Dover's landmark study "Greek Homosexuality", Greek art had extreme interest in the genitals, but was not obsessed with size. The weekly Q&A column "The Straight Dope" deduces, based on pornographic Greek art work and Dover's aforementioned study, that in ancient Greece an uncircumcised and small penis was culturally seen as desirable in a man, whereas a bigger or circumcised penis was viewed as comical or grotesque, usually being found on "fertility gods, half-animal critters such as satyrs, ugly old men, and barbarians."[31]

CBC Radio has suggested, based on several sources, that ancient Romans had a viewpoint contrary to that of the Greeks.[30] This was also the case in medieval Arabic literature, where a longer penis was preferred, as described in an Arabian Nights tale called "Ali with the Large Member". As a witty satire of this fantasy, the 9th-century Afro-Arab author Al-Jahiz wrote: "If the length of the penis were a sign of honor, then the mule would belong to the Quraysh" (the tribe to which Muhammad belonged and from which he descended).[32]

Penis size is also alluded to in the Bible:

18When she carried on her whoring so openly and flaunted her nakedness, I turned in disgust from her, as I had turned in disgust from her sister.19Yet she increased her whoring, remembering the days of her youth, when she played the whore in the land of Egypt20and lusted after her lovers there, whose members were like those of donkeys, and whose issue was like that of horses. Ezekiel 23:18–20, English Standard Version.

Male self-perception
Males may quite easily underestimate the size of their own penis relative to that of others, because of the foreshortening obtained from looking down, due to repeated observation of atypical penises in pornography, or because of the accumulation of fat at the base of the penis.[33] A survey by sexologists showed that many men who believed that their penis was of inadequate size had average-sized penises.[34] Another study found sex education of standard penile measurements to be helpful and relieving for patients concerned about small penis size, most of whom had incorrect beliefs of what is considered medically normal.[35] The perception of having a large penis is linked to higher self-esteem.[3]

Among gay men
A study undertaken at Utrecht University found that the majority of homosexual men in the study regarded a large penis as ideal, and having one was linked to self-esteem.[36] One study analysing the self-reported Kinsey data set found that the average penis of a homosexual man was larger than the average penis of their heterosexual counterparts (6.32 inches [16,05 cm] in length amongst gay men versus 5.99" [15,21 cm] in heterosexuals, and 4.95 inches [12,57 cm] circumference amongst gay men versus 4.80" [12,19 cm] in heterosexual men).[37][38]

Anxiety about penis size
Widespread private concerns related to penis size have led to a number of folklore sayings and popular culture reflections related to penis size. Penis panic is a form of mass hysteria involving the believed removal or shrinking of the penis, known as genital retraction syndrome. The penis can significantly shrink due to scar tissue formation from a condition called Peyronie's disease which affects up to 10% of men.[39] Products such as penis pumps, pills, and other dubious means of penis enlargement are some of the most marketed products in email spam. At present there is no consensus in the scientific community of any non-surgical technique that permanently increases either the thickness or length of the erect penis that already falls into the normal range (4.5" to 7").[40]

Penis size and size of other body parts
A statistically significant correlation between penis size and the size of other body parts has not been found in research. One study, Siminoski and Bain (1993), found a weak correlation between the size of the stretched penis and foot size and height; however, it was too weak to be used as a practical estimator.[41] Another investigation, Shah and Christopher (2002), which cited Siminoski and Bain (1993), failed to find any evidence for a link between shoe size and stretched penis size, stating "the supposed association of penile length and shoe size has no scientific basis".[42][43]

There may be a link between the malformation of the genitalia and the human limbs. The development of the penis in an embryo is controlled by some of the same Hox genes (in particular HOXA13 and HOXD13)[44] as those that control the development of the limbs. Mutations of some Hox genes that control the growth of limbs cause malformed genitalia (hand-foot-genital syndrome).[45]

Studies of size preferences among sexual partners
In a small study conducted by University of Texas–Pan American and published in BMC Women's Health, 50 undergraduate women were surveyed by two popular male athletes on campus about their perceptions of sexual satisfaction and it was concluded that the width of a penis feels better than the length of a penis, when subjects are asked to choose between the two (size was left unspecified). It was also concluded that this may show that penis size overall affects sexual satisfaction since women chose between the two options they were given.[46]

In a cover story by Psychology Today,[47][48] 1,500 readers (about two-thirds women) were surveyed about male body image. Many of the women were not particularly concerned with penis size and over 71% thought men overemphasized the importance of penis size and shape. Generally, the women polled cared more about width than men thought, and less about length than men thought, although the strength of caring for either among women showed a similar pattern.

Another study, conducted at Groningen University Hospital, asked 375 sexually active women (who had recently given birth) the importance of penis size the results of which showed that 21% of women felt length was important and 32% felt that girth was important.[49]

A study conducted at the Australian National University, published in early 2013, showed that penis size influences a man's sex appeal, and the taller the man, the bigger the effect.[50] The study showed 3D computer generated images at life size, altering the height and other physical attributes, with women typically registering preferences in under 3 seconds. A preference for taller men's larger penis size was notable.

The term size queen is slang for anyone who prefers their sexual partner(s) to have a larger-than-average penis.[51]

Evolution
See also: Sexual selection in human evolution § Sexual anatomy
The human penis is thicker than that of any other primate, both in absolute terms and relative to the rest of the body.[52] Early research, based on inaccurate measurements, concluded that the human penis was also longer. In fact, the penis of the common chimpanzee is no shorter than in humans, averaging 14.4 cm (5.7 inches), and some other primates have comparable penis sizes relative to their body weight.[53]

The evolutionary reasons for the increased thickness have not been established.[54] One explanation is that thicker penises are an adaptation to a corresponding increase in vaginal size. The vaginal canal is believed to have expanded in humans to accommodate the larger size of a newborn's cranium. Women may then have sexually selected men with penises large enough to fit their vagina, to provide sexual stimulation and ensure ejaculation.[54]

Penis size and condom use
One Australian study of 184 men looked at penis length and circumference in relationship to condom breakage or slippage. 3,658 condoms were used. The study found that when used correctly condoms had a breakage rate of 1.34% and a slippage rate of 2.05%, for a total failure rate of 3.39%. Penile dimensions did not influence slippage, but penis circumference and broken condoms were strongly correlated, with larger sizes increasing the rate of breakage.[55]

Average Penis Size and Other Interesting Facts



A man's penis can provide great pleasure but sometimes significant anxiety as well. Anxiety normally arises from feelings of inadequacy with size, strength of erection and sexual performance. Here, we just want to provide you with some interesting facts about the penis and possibly help you answer the question: is my penis size large enough to satisfy a woman?
Let's start with the penis attribute of most interest: size.

Average Penis Size

In a report published in BJU International, researchers brought together results of 12 studies that measured penis size and 11,531 men since 1942.  They also studied what men and women think about penis size.  63% of men with average penis size felt that they were big enough.  However, 85% of women were satisfied with their partner's size.
Average Penis Size by RaceAccording to a 1,661 men study published in the July 10, 2013 Journal of Sexual Medicine, the average erect penis is about 5.5 (14 cm) long, ranging from 1.6 inches (4cm) long to 10.2 inches (26 cm). However, the standard deviation is about 1 inch (2.66 cm) which means that, about two-thirds of men's erect penises in the study are between roughly 4.5 and 6.5 inches long (12.5cm to 16.8cm).  Another way to look at this is that almost 20% of men have an erect penis size of less than 4.5 inches, or 1 inch shorter than the average. Race is often a topic of conversation with respect to penis size but the data shows only modest variation.
Go the this page for information about penis enlargement pills and other methods to help increase the size of your penis.

Penis Extenders - Do the Work?

Mayo Clinic reviewed several studies which have shown 1-2 centimeters increase in penis size using these devices but says that the studies were not of high quality and that more rigorous testing must be performed. Cornell University summarized a study in the Journal of Sexual Medicine that showed a mild increase in penis length with daily use of the Fastsize product for the treatment of Peyronie's disease.  

Interesting Facts About Penis Size

  • Flaccid length not predictor of erect length.  Some men have relatively short flaccid penises but typically expands when erect to a "normal" length.  These types of penis are referred to as grow-ers. The other appears big most of the time, but doesn't get much bigger after achieving erection .. a show-er.
  • An international Men's Health survey reports that 79 percent of men have grow-ers, 21 percent have show-ers.
  • Only 6 percent of the male population needs extra-large rubbers, according to condom manufacturers.
  • Most men underestimate the size of their penis.
  • Contrary to popular opinion, there's no correlation to height, foot size, etc.
  • And because it reduces blood flow to the penis, smoking can shorten the average penis by up to 0.4 inches (1 cm)

Erections

  • Aside from size, there are a number of interesting facts about erections. You can learn the physiology of achieving an erection on our erectile dysfunction page.
  • Most apes have a bone, or baculum, to keep their penis erect. Humans rely solely on blood pressure. Biologists do not know why humans selectively lost this trait, but walking upright with this bone may seem a little uncomfortable.
  • Even a little tiny fetus can have an erection. Ultrasound tests have shown that it can happen in the third trimester.
  • Men have "spontaneous" erections during the day that have nothing to do with arousal.
  • Erections also occur while sleeping are common and there is even a medical term for it - Nocturnal Penile Tumescence, or NPT.  Men average about five erections per night.
    • NPT often occurs during REM sleep where it is believed that the brain stops releasing a chemical the normally suppresses erections.
    • NPT also occurs for men with a full bladder - a type of reflex erection, suggesting a mechanism to prevent urination while sleeping (nocturnal enuresis). A common slang term for the full bladder NPT is "morning wood".
    • NPTs are believed to contribute to penis health.
  • Although no formal studies have been published, based on astronaut tales, it is difficult - perhaps not possible - for men to achieve an erection in space. Apparently, gravity plays a role.

Penis Sensitivity

Fine touch measurements of penis sensitivity
Men generally slowly lose penis sensitivity with age with a sharper decline starting around age 65. Many healthy men under 65 report having too much sensitivity and not being able to control ejaculation. 
It's difficult for men to do a self-evaluation of the level of sensitivity. However, debate about the positives and negatives of circumcision has led to a number of studies related to penis sensitivity and pleasure. 
Using this information provides men with an indication of comparing his feeling of sexual stimulation  with other men. Two studies from the British Journal of Urology (BJU International) provide excellent data on penis sensitivity from two viewpoints. The first is based on actual touch testing and the other based on men recalling recent sexual experiences and pleasure locations.

Fine-touch Measurements

In research presented in the article Fine Touch Pressure Thresholds in the Adult Penis, Sorrels, et. al. published in BJU International in 2007, a fine-touch measurement device was used to determine male sensitivity to light stimuli while erect. This would be akin to using a feather.  As you can see in the images of measurements from a circumcised penis, the male penis has quite a bit of variation in fine-touch sensitivity.  It should be noted that for intact (non-circumcised ) men, the frenulum are is highly sensitive with thresholds between 0 and 0.2.
The scar/ventral from circumcision is the most sensitive area of penis, even more so than the frenulum area.

Self-Assessment of Sexual Pleasure

In a 2009 study by the British Journal of Urology, researchers surveyed 119 healthy men to assess their genital anatomy with respect to sexual sensitivity. 
Male Sexual Sensitivity by Gential Area
The frenulum area of the penis is identified by men as the most sensitive. This is also the area that many urologist experts recommend as the first location to apply a topical desensitizer to control ejaculation. Anecdotal evidence from PE patients target the underside of the penile shaft as the second most sensitive area and the glans (head) third, both of which aligns with this data.
There are two major differences between the fine-touch measurements and the self-assessment. The first is that the fine-touch measurements identify 19 locations on the penis while the self-assessment only seven. This makes sense. The fine-touch device can pinpoint specific locations on the penis while most penile sexual stimulation is over a larger surface area of the penis.  
The other major difference is pressure.  Most sexual stimulation - vaginal, oral, anal, manual, toy -  is not "fine touch"; it's significantly higher pressure.  As an example, a male can easily masturbate to orgasm purely by manually stimulating his shaft under the skin's surface with a relatively strong grip on the penis, moving the penis skin over the shaft. The conclusion is that penile stimulation to orgasm is complicated, not well understood and certainly involved nerves below the surface of the penile skin.
New data let men take a closer look at how they stack up.
ANDREY POPOV/SHUTTERSTOCK
New data let men take a closer look at how they stack up.

How big is the average penis?

“I was in the pool!” George Costanza’s distress at the “shrinkage” of his penis after exiting a cold pool was hilarious in the 1994 Seinfeldepisode, but for many men concern over the length and girth of their reproductive organ is no laughing matter. Now, a new study could assuage such worries with what may be the most accurate penis-size measurements to date.
Many earlier studies relied on self-reporting, which doesn’t always yield reliable results. “People tend to overestimate themselves,” says David Veale, a psychiatrist at the South London and Maudsley NHS Foundation Trust. So when Veale and his team set out to settle the score on penile proportions, they decided to compile data from clinicians who followed a standardized measuring procedure.
Published today in the British Journal of Urology Internationaltheir new study synthesizes data from 17 previous academic papers that included measurements from a total of 15,521 men from around the world. The data enabled the researchers to calculate averages and model the estimated distribution of penile dimensions across humanity. “It still just strikes me how many men have questions and insecurities and concerns about their own penis size. We actually do need good data on it,” says Debra Herbenick, a behavioral scientist at Indiana University, Bloomington, who was not involved in the study.
According to the team’s analysis, the average flaccid, pendulous penis is 9.16 cm (3.61 inches) in length; the average erect penis is 13.12 cm (5.16 inches) long. The corresponding girth measurements are 9.31 cm (3.66 inches) for a flaccid penis and 11.66 cm (4.59 inches) for an erect one.
A graph of the size distribution shows that outliers are rare. A 16-cm (6.3-inch) erect penis falls into the 95th percentile: Out of 100 men, only five would have a penis larger than 16 cm. Conversely, an erect penis measuring 10 cm (3.94 inches) falls into the 5th percentile: Only five out of 100 men would have a penis smaller than 10 cm.
Gentlemen, if you’re eager to see how you measure up, you’ll need to follow the same measurement procedure used in the study. All length measurements were made from the pubic bone to the tip of the glans on the top side of the penis. Any fat covering the pubic bone was compressed before measurement, and any additional length provided by foreskin was not counted. Circumference was measured at the base of the penis or around the middle of the shaft, as the two sites were deemed equivalent.
The researchers concluded that there was no strong evidence to link penis size to other physical features such as height, body mass index, or even shoe size. Yes, it seems that the only definite conclusion that can be drawn about a fellow with big socks is that he probably has big feet. Likewise, the study found no significant correlation between genital dimensions and race or ethnicity, although Veale points out that their study was not designed to probe such associations, because much of the data used were from studies of Caucasian men.
It’s easy to laugh at poor George Costanza for his shrunken manhood, but some reports suggest that only about 55% of men are satisfied with their penis size. Some seek potentially dangerous surgical solutions to a problem that, according to Veale, is often only in their head. Men “seem to have a very distorted picture of what [size] other men are, and what they believe they should be,” Veale says.
Pornography, in which male performers are often selected for their extremely large genitalia, may be partly to blame. Similarly, Herbenick points to the myriad spam e-mails that assert that 17.78 cm (7 inches) is average for an erection, when in reality such a member would place its owner in about the 98th percentile. It’s best to just ignore those ads in any case, Veale says. “There are no effective lotions or potions or pills.”
Posted in Biology
Science| DOI: 10.1126/science.aaa7934
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References
Notes
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