Human penis size
Regarding the length of the adult fully erect penis (measured along the top of the penis from the groin to the tip), several studies have been performed. Those studies that relied on self-measurement consistently reported a higher average than those that had staff take the measurements.
- An UCSF study by Wessells et.al. published in 1996 found an average of 5.1 inches (13.0 cm). (Measured by staff)
- A study by a Brazilian urologist found an average of 5.7 inches (14.5 cm). (Measured by staff)
- A German study in 1996 also reported an average of 5.7 inches (14.5 cm). (Measured by staff)
- A study conducted by LifeStyles Condoms during 2001 Spring Break in Cancun found an average of 5.9 inches (15.0 cm). (Measured by staff)
- A study conducted by the Korean Consumer Protection Board (KCPB) at a college campus found an average of 6.1 inches (15.5 cm).
- The longest erect penis on record is around 12 inches (30 cm). The shortest erect penis on record is under 1/2 an inch (1.3 cm), not counting cases where men are born without a penis.
Similarly, regarding the circumference of the adult fully erect penis (with the measurement taken from the midshaft of the penis), several studies have been performed. Just as with length, those studies that relied on self-measurement consistently reported a higher average than those that had staff take the measurements.
- An UCSF study by Wessells et.al. published in 1996 found an average of 4.9 inches (12.5 cm). (Measured by staff)
- A study by a Brazilian urologist found an average of 4.7 inches (12.0 cm). (Measured by staff)
- A study conducted by LifeStyles Condoms during 2001 Spring Break in Cancun found an average of 5.0 inches (12.7 cm). (Measured by staff)
- A study conducted by the Korean Consumer Protection Board (KCPB) at a college campus found an average of 5.0 inches.
There is an ongoing government study in India commissioned with the goal of helping reduce the high condom failure rate there.
The flaccid penis is measured when fully stretched, from the belly to the tip, excluding the foreskin. The length of a stretched flaccid penis closely conforms to erect length.
Average stretched penile length at birth is about 4 cm, and 90% of newborn boys will be between 2.4 and 5.5 cm (0.94 and 2.17 inches). 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 with adult size reached about 5 years later. W.A. Schonfeld published a penis growth curve in 1943.
Regarding the length of the adult flaccid fully stretched penis:
- Lee et.al. reported in 1980 an average of 13.3 cm (5.24 inches) with a standard deviation of 1.6 cm (0.63 inches)
- Sutherland et al reported in 1996 an average of 12.4 cm (4.9 inches) (std. dev. 2.7cm or about 1 inch) in Caucasian peoples, an average of 14.6 cm (5.7 inches) in blacks, and an average of 5.6 cm (2.2 inches) in Asian peoples. This study neglects to take into account height and weight, which may be the primary indicator of penis size.
The length of the unstretched flaccid penis is no guide to the size of the erect penis; indeed, some men with small flaccid penes may have larger erections than men with larger flaccid penis. When a man with a relatively large flaccid penis has a normal or below average length penis when fully aroused, or when a man with a relatively small flaccid penis has a normal or above average length penis when fully aroused, they are known by the slang terms "showers" and "growers" respectively.
Present environmental conditions play a role in the size of a relaxed flaccid penis, in particular cool temperatures. One general physiological response to cold is decreased circulation of blood to the appendages. As the size of the penis very much relies on blood supply, this results in a decreased flaccid size. The slang term "shrinkage" is sometimes used to describe this phenomenon, and was featured in a famous episode of Seinfeld. As humorist Garrison Keillor once said, "At forty degrees below zero, all men are indeed equal."
In a 2005 study by the University of California Los Angeles, 45% of men responded they would prefer their penis size increased. 84% of respondents rated their penis size as average to above average. There is a similar perception gap in women's perceptions of their breasts. (See: Human Breast Size) 70% desired more ample or rounder breasts.
Men may tend to misjudge the size of their penis relative to that of other men they have seen naked, simply because of the foreshortening effect obtained from always looking down at the penis from above. In addition, as Paul Fussell noted in his memoirs, men who are overweight or have large stomachs may fail to allow for the partial concealment of the penis by their abdominal region. The build up of fat on the pubic bone above the penis may give a shorter appearance even though the length of the penis from the base is normal.
A survey by sexologists showed that many men who believed that their penis was of inadequate size actually had a normal-sized penis. Most sexologists believe that worries about penis size come from some other source of anxiety or perceived inadequacy.
In some cultures, mass hysteria involving the believed removal or shrinking of the penis has been observed. See penis panic for a detailed discussion.
Many theories are held in popular culture, that it is possible to predict the size of someone's penis by observing other features. The features usually selected are
- Size of hands
- Size of feet, or shoe size
- Size of nose
Many place great stock in these theories; however, no actual statistical evidence correlating penis size to any other part of the body exists. The shoe size theory does not hold up under statistical analysis controlled for body height.
One of these theories says that the size of a fully erect penis is the length from the tip of a man's thumb to the tip of his index finger, when a 90° angle is made with those two fingers.
Main article: Micropenis
A penis whose stretched flaccid length is more than approximately 2.5 standard deviations below average size for the age group but otherwise formed normally is referred to in a medical context as a micropenis. 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 HOX9 gene variations. Some types of micropenis can be improved with growth hormone or testosterone treatment in early childhood. Penis-enlargement self-treatments are not effective for this condition.
A news post on New Scientist dated Dec 6, 2004 reads "A new surgical procedure has allowed men with abnormally short penises to enjoy a full sex life and urinate standing up, some for the first time. Tiny "micro-penises" have been enlarged to normal size without losing any erogenous sensation, say UK doctors."
Recently, there has been greater media attention to the issue of penis size and women being more vocal about their preferences. Television shows such as Sex and the City and Ally McBeal popularized the penis size issue when characters in these TV shows stated their preference for well-endowed men and rejected men who had only average endowment. In one of these shows, a female character is portrayed crying in bed when she sees her boyfriend's penis for the first time and discovers that it is of only average length, as opposed to the large length she had expected and anticipated. On one episode of Sex and the City, the characters debate whether it's proper to dump a man because of displeasure over the size of his penis; they conclude that it's OK and at the end of the episode one of the women does indeed dump her boyfriend because she doesn't like the size of his penis.
The media image of women's preference may have had an impact on some average sized men, and caused even more damage to below-average sized men who are likely already self conscious. In recent years, penis pumps, pills, and other dubious means of penis enlargement have had increased sales.
Surveys of women's actual preference have consistently shown that penis size is only a priority for a minority of women, and some women dislike large penises. The media has been criticized for making "penis envy" into a male body issue equivalent to Cosmopolitan Magazine being criticized for their coverage of women's weight. Indeed, one episode of Sex and the City also shows a character expressing displeasure over her partner having too large of a penis.
A Dutch study found in 2002 that 20-30% of women consider the size of a penis to be important.
Race and penis size
The question of race and penis size is controversial, and has not been definitively established. There have been many studies with claims of varying rigor—for example, the LifeStyles condoms study—but they are generally flawed by selection bias. Frantz Fanon covers this subject in some detail in Black Skin, White Masks (1952), where he tends towards the view that the supposed positive correlation between large penises and African ancestry is a myth, a conclusion that he backs up with statistics. On the other hand, J. Philippe Rushton has published statistics claiming otherwise (Race, Evolution, and Behavior: A Life History Perspective, 1995).
Allen's rule and Bergmann's Rule propose that warm-blooded animals (which includes mammals) in warmer climates tend to have a higher surface-area-to-volume ratio, to aid in heat dissipation. The size and thickness of appendages contribute to this ratio.
- Wessells H, Lue TF, McAninch JW. "Penile Length in the Flaccid and Erect States: Guidelines for Penile Augmentation," Journal of Urology, Vol. 195, 995-997, 1996.
- The Kinsey Institute penis size bibliography
- Sutherland et al. "The effect of prepubertal androgen exposure on adult penile length." Journal of Urology, Vol. 156(2S), 783-787, 1996.
- Lee PA, et al. "Micropenis. I. Criteria, etiologies, and classification." Johns Hopkins Med J 1980; 146:156.
- W.A. Schonfeld, Am J Dis Child 1943;65:135
- Niels Lauersen, M.D. and Steven Whitney, "It's Your Body: A Woman's Guide to Gynecology", 3rd Edition 1983, p. 480 (Brerkley Publishing Co.: New York), ISBN 0425099172
- Penis envy
- Percy, a 1970 comedy film about an unusually large penis being transplanted
- Jonah Falcon
- Tommy Lee
- John Holmes
- "Measurection.com" Discussion board dedicated to helping men accept their penis size and themselves.
- "Definitive Penis Size Survey" Internet-based, self-reported and appears to have exaggerated data.
- Penis Size Links List Comprehensive listing of online resources. (Note: advertises pornography.)
- Penis size based on body parts Investigation into myth that Hands/feet/nose are an indicator of penis size
- The Illustrated Book of Sexual Records See Largest/Smallest human penis (by race); Largest penis by sex offender class
- The Penis Website About the Penis and Male Sexuality (Note: advertises pornography.)
- Dr. Nick Summary Penis Size data
- Kinsey Institute page on the penis
- Ask Men page about penis
- Race, Sex and Myths:Images of African American Men and Women
- Sexual Averages
- A legend from the Trobriand Islands about a man with a very long penis
- Matters of Size Another discussion board dedicated to penis enlargement methodology.fi:Peniksen koko