Individual differences |
Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology |
Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Neuroscience · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology (Index, Outline)
When compared to other primates, including large primates such as the gorilla, the male human genitalia are remarkably large. The human penis is both longer and thicker than that of any other primate both in absolute terms and in relative size to the rest of the body. Contrary to popular belief, there is no scientific relation between penis size and race.
Measuring the penis
To get the most accurate measurements for an individual's penis size, it has been recommended that several measurements be taken at different times, preferably with different erections on different days. The measurements are then to be averaged together. This is to account for what may be natural variability in size due to factors such as arousal level, time of day, room temperature, frequency of sexual activity, and unreliability of the measurement methods.
The length can be measured with the subject standing and the penis held parallel to the floor. The penis is measured along the top, from the base to the tip. Results are inaccurate if the measurement is taken along the underside of the penis, or if the subject is seated or prone.
Penis girth is the measurement of the circumference of the completely erect penis. It is variously quoted as an average of three measurements: just below the glans penis, in the middle of the shaft, and at the base.
A penis must be completely erect in order to obtain an accurate measurement. This may be difficult to achieve in a clinical setting. At least one Brazilian doctor resorted to injecting penises with drugs to induce erection, which gave more consistent results. Some clinicians measure the penis by stretching the flaccid penis as far as comfortably possible.
Studies on penis size
While results vary across studies, the consensus is that the mean human penis is approximately 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). The typical girth or circumference is approximately 12.3 cm (4.85 in) when fully erect. The mean penis size is slightly greater than the median size.
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 (0.9 and 2.2 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.
Size with aging
Authors of a paper reviewing research on area of penis sizes conclude that "flaccid penile length is just under 4 cm at birth and changes very little until puberty, when there is marked growth."
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].”
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.
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.
- A study published in the September 1996 Journal of Urology concluded that average erect length was 12.9 cm (5.08 in) (measured by staff). 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 (5.35 in) (measured by staff). 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 study conducted by LifeStyles Condoms found an average of 14.9 cm (5.9 in) with a standard deviation of 2.1 cm (0.8 in) (measured by staff). The purpose of this study was to ensure properly sized condoms were available.
- A review published in 2007 issue of BJU Internetional, have shown that average erect penis length is 14–16 cm and its girth is 12–13 cm. This paper compares results of twelve studies conducted on different populations in several countries.
- An Italian study of about 3,300 Italian men concluded that stretched length was measured on average to about 5 inches. In addition, a correlation between weight and height and penis length was also found. However this was done only on 500 men with a small correlation value.
- The Cancún LifeStyle study, in which the circumference of the shaft was measured at three points (base, mid-shaft, and just below the head) and then averaged, found an average of 12.63 cm (4.972 inches) with a standard deviation of 1.3 cm (0.5 in).
Similar results exist regarding studies of the circumference of the adult fully erect penis, with the measurement taken mid-shaft. As with length, studies that relied on self-measurement consistently reported a significantly higher average than those with staff measuring.
One study found the mean flaccid penis length to be 3.5 inches (8.9 cm) (measured by staff). A review of several studies have shown average flaccid length to be 9–10 cm. Length of the flaccid penis does not necessarily correspond to length of the erect penis; some smaller flaccid penises can grow much larger, and some larger flaccid penises cannot grow much larger.
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 issue affects cyclist and exercise bike users, with prolonged pressure on the perineum from the saddle, and the straining of the exercise causing the penis and scrotum to contract involuntarily which is sometimes referred to as "gym balls" or "saddle balls". An incorrect saddle may ultimately cause erectile dysfunction (see crotch pressure for more information).
Penises that are short when flaccid but more average when erect are colloquially known as growers, where those with greater flaccid lengths that increase little when erect are known as showers.
Flaccid penis length is a poor estimate of erect length, a better estimate is stretched length, that is 12–13 cm, as shown in review by Wylie and Erdley.
Penis enlargement surgery
- Main article: Penis enlargement
Most men concerned about their penis size and seeking surgical treatment to enlarge their penis overestimate "normal" penis length. All of the patients studied by Mondaini et al seeking surgical treatment had penis size within the normal range.
Surgical techniques used for penis enlargement (enhancement phalloplasty) – penis lengthening and penile widening (girth enhancement) – have been in the urologic literature for many years.
There are two basic ways of enlarging the penis:
- Penis lengthening surgery involves the release of the fundiform ligament and the suspensory ligament that attaches the 2 erectile bodies to the pubic bone. Once these ligaments have been cut, part of the penile shaft (usually held within the body) drops forward and extends out, enlarging the penis by 2–3 cm.
- Penis widening with PMMA injection. This method involves injection of silicone, PMMA and other materials into the penis and scrotum to achieve girth enlargement.
Perceptions of penis size
In ancient Greek art, it is common to see smaller male genitalia than one would expect for the size of the man. Renaissance art also followed this aesthetic; note Michelangelo's David. 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 (at least in the high-brow view), usually being found on "fertility gods, half-animal critters such as satyrs, ugly old men, and barbarians."
CBC radio has suggested, based on several sources, that ancient Romans had a viewpoint contrary to that of the Greeks. 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 (honorable tribe of) Quraysh".
Modern perceptions and sexual preference
Males may quite easily underestimate the size of their own penis relative to that of others, because of the foreshortening obtained from looking down, or because of the accumulation of fat at the base of the penis. A survey by sexologists showed that many men who believed that their penis was of inadequate size had average-sized penises. 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. One source of continued debate is the extent to which women actually prefer certain penis sizes.
A 2005 Internet survey of 52,031 heterosexual men and women found only 55% of participating men were satisfied with their penis size, whereas 85% of participating women said they were "very satisfied" with the size of their partner's penis, and only 6% of women rated their partner as smaller than average. In the same data set, 70% of women expressed dissatisfaction with their breasts, whereas the majority of men (56%) were satisfied with their partner's breasts and only 20% of men wished their partner had larger breasts.
A study published in BMC Women's Health, surveyed women's preferences concerning penis size and concluded that width rather than length is a more important factor of sexual stimulation.
Similar results were found in a cover story published in Psychology Today, which surveyed 1,500 readers (about 2/3 women) 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. Details were examined among the women with a size preference. Generally women cared more about width than men thought, and less about length. "...the number one reason women preferred a thicker penis was that it was more satisfying during intercourse." It's suggested this is because a wider penis provides more friction to the clitoral area while a longer penis reaches an area less stimulable. The same article comments that there is a strong correlation whereby “Women who rated themselves as more attractive were particularly concerned with larger size. Of women describing themselves as 'much more attractive than average,' 64% cared strongly or moderately about penis width and 54% cared about penis length. Women who rated their own looks as average were about 20 percentage points lower."
Another study, conducted at Groningen University Hospital, asked 375 sexually active women (who had recently given birth) the importance of penis size and concluded: "Although clearly in the minority, a nevertheless considerable percentage of the women respondents attached substantial importance to the size of the male sexual organ".
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.
Widespread private concerns related to penis size have led to a number of folklore sayings and popular culture reflections related to penis size. These include beliefs that it is possible to predict the size of someone's penis by observing other bodily features such as the hands, feet, nose or height, and in some cases so-called "penis panic" - a form of mass hysteria involving the believed removal or shrinking of the penis, known as genital retraction syndrome. Penis size, and sexual anxiety generally, have led to products such as penis pumps, pills, and other dubious means of enlargement becoming some of the most marketed products in spam mail.
The suggested link between penis size, foot size and height has been investigated by a relatively small number of groups. Two of these studies have suggested a link between penis size and foot size, while the most recent report dismissed these findings. One of the studies suggesting a link relied on the subjects measuring the size of their own penis, which may well be inaccurate. The second study found statistically significant although "weak" correlation between the size of the stretched penis and foot size and height A potential explanation for these observations is that the development of the penis in an embryo is controlled by some of the same Hox genes (in particular HOXA13 and HOXD13) 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). However the most recent investigation failed to find any evidence for a link between shoe size and stretched penis size. Given the large number of genes which control the development of the human body shape, and the effects of hormones during childhood and adolescence, it would seem unlikely that an accurate prediction of penis size could be made by measuring a different part of the human body.
Other studies correlating the size of the human penis with other factors have given intriguing results. Notably one study analysing the self-reported Kinsey data set found that homosexual men had statistically larger penises than their heterosexual counterparts. One potential explanation given is a difference in the exposure to androgen hormones in the developing embryo. The study author's opinion is that evidence points towards both orientations being equally likely to exaggerate.
Penis size and female genital response
According to some sex researchers and therapists, several misconceptions have developed surrounding penile-vaginal intercourse. Many men exaggerate the importance of deep vaginal penetration in stimulating a woman to orgasm.[who?]
The most sensitive area of the female genitals includes the vulva, clitoris, and the section of vagina closest to the outside of a woman's body, which is roughly 10 centimeters (4 in) in length. Research has found that portions of the clitoris extend into the vulva and vagina. Given that the median penis size is above this length, the majority of penises are likely of sufficient length to fully satisfy their partners.
While many women find penile stimulation of the cervix to be uncomfortable or painful, others report it to be key to orgasm. The cervix may be confused with the anterior or posterior fornix, the deepest point of the vagina, above and below the cervix, respectively. The cervix and fornix are close to each other, making it possible for there to be indirect and/or simultaneous stimulation between them.
The fornix is said to be another possible orgasm trigger area. Tests have shown that pressure on this area causes the vagina to lubricate very quickly. The area of sexual response in the anterior fornix has also been called the epicentre, T-Spot, AFE-Zone, AFE or A-Spot; while in the posterior fornix it has been called epicenter (as well) or cul-de-sac (since the cul-de-sac, also known as the rectouterine pouch, may be indirectly stimulated by pressure on the posterior fornix).
During arousal, the vagina lengthens rapidly to an average of about 10 centimeters (4 in), but can continue to lengthen in response to pressure. As the woman becomes fully aroused, the vagina tents (last Template:Frac expands in length and width) while the cervix retracts. The walls of the vagina are composed of soft elastic folds of mucous membrane skin which stretch or contract (with support from pelvic muscles) to the size of the penis. This means (with proper arousal) the vagina stretches or contracts to accommodate virtually any size penis, from small to large.
Other variance in penis size
- Main article: Micropenis
An adult penis with an erect length of less than 7 cm or just over 2 inches but otherwise formed normally is referred to in a medical context as having the micropenis condition. The condition affects 0.6% men. 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.
A news post on New Scientist dated December 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."
Environmental influence on penis size
It has been suggested that penis size differences between individuals is caused not only by genetics, but also by environmental factors such as culture, diet, chemical/pollution exposure, etc. Endocrine disruptor 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, etc...) and natural (e.g. chemicals found in tea tree oil and lavender oil) sources have been linked to various degrees of endocrine disruption. Both Polychlorinated biphenylPCBs and the plasticizer DEHP have been associated with smaller penis size. DEHP metabolites measured from the blood 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. Approximately 25% of US women have phthalate levels similar to those in the study.
Penis size and condom use
Various studies have examined condom breakage. Ninety-two monogamous heterosexual couples (aged 18 to 40 for women, 18 to 50 for men) were enrolled in a prospective study of Durex Ramses condoms. At each sexual encounter, a diary was completed which included information on condom use, and breaks and slips. In France a random telephone survey of 20,000 individuals drew on 4,500 sexually active people, of whom 731 had used a condom in the previous year and 707 provided information on difficulties of use. In Australia 3,658 condoms were used by 184 men in a study which looked, among other things, at penis size as a factor for breakage or slippage.
Although the most common type of condom, those made of latex, have great ability to stretch, they are vulnerable to dry friction (ie, the dry rubbing motion of sexual activity when there is tight pressure or a lack of smooth lubricated movement) as well as other mistakes of usage. For example, in a separate study of people practicing anal sex, condom breakage was linked more to excessive friction (in this case due to low usage of a sexual lubricant) than to penis size per se.
The rate of condom breakage for correctly used condoms was 1.34% and of slippage 2.05%, with a total failure rate of 3.39%. Penis size did not influence slippage, but penis circumference and broken condoms were strongly correlated, with larger sizes increasing the rate of breakage.
- ↑ Small, Meredith F. (1995). What's Love Got to Do With It? The Evolution of Human Mating, Anchor Books.
- ↑ Adams, Michael V (1996). The multicultural imagination: race, color, and the unconscious, London: Routledge.
- ↑ "Penis Myths Debunked". LiveScience. June 1, 2007.
- ↑ 4.0 4.1 4.2 Bertman, Jonathan Correctly measuring your erection: Length & circumference.Template:Self-published inline
- ↑ Harding R, Golombok SE (August 2002). Test-retest reliability of the measurement of penile dimensions in a sample of gay men. Archives of Sexual Behavior 31 (4): 351–7.
- ↑ Penis Size Survey. Ansell.
- ↑ Smith DP, Rickman C, Jerkins GR (August 1995). Ultrasound evaluation of normal penile (corporeal) length in children. The Journal of Urology 154 (2 Pt 2): 822–4.
- ↑ 8.0 8.1 8.2 Wessells H, Lue TF, McAninch JW (September 1996). Penile length in the flaccid and erect states: guidelines for penile augmentation. The Journal of Urology 156 (3): 995–7.
- ↑ 9.0 9.1 Chen J, Gefen A, Greenstein A, Matzkin H, Elad D (December 2000). Predicting penile size during erection. International Journal of Impotence Research 12 (6): 328–33.
- ↑ 10.0 10.1 10.2 10.3 (2001). ANSELL RESEARCH - The Penis Size Survey. Ansell. URL accessed on 2006-07-13.
- ↑ Schonfeld, William A. (April 1943). Primary and secondary sexual characteristics: Study of their development in males from birth through maturity, with biometric study of penis and testes. Archives of Pediatrics & Adolescent Medicine 65 (4): 535–49.
- ↑ 12.0 12.1 12.2 12.3 12.4 Wylie KR, Eardley I (June 2007). Penile size and the 'small penis syndrome'. BJU International 99 (6): 1449–55.
- ↑ 13.0 13.1 Aitken, Paul What's Average?. URL accessed on 2007-11-09.
- ↑ "A sample that is not representative of the population to which generalizations are to be made. FOR EXAMPLE, a group of band students would not be representative of all students at the middle school, and thus would constitute a biased sample if the intent was to generalize to all middle school students."Bureau of Justice Assistance website
- ↑ Ponchietti R, Mondaini N, Bonafè M, Di Loro F, Biscioni S, Masieri L (February 2001). Penile length and circumference: a study on 3,300 young Italian males. European Urology 39 (2): 183–6.
- ↑ (1988). Penis size increase between flaccid and erect states: An analysis of the Kinsey data. The Journal of Sex Research 24: 177–83. See also Kinsey Institute's Penis Size FAQ & Bibliography
- ↑ Mondaini N, Ponchietti R, Gontero P, et al. (August 2002). Penile length is normal in most men seeking penile lengthening procedures. International Journal of Impotence Research 14 (4): 283–6.
- ↑ Suspensory Ligament Surgery for Penis Enlargement Blog
- ↑ Penis enlargement Surgery: Myths and Facts
- ↑ 20.0 20.1 Phallus in Wonderland. CBC Radio. URL accessed on 2007-11-13.
- ↑ Adams, Cecil Why does so much ancient Greek art feature males with small genitalia?. The Straight Dope. URL accessed on 2006-08-05. "From this vast array of XXX-rated artwork we can make a few deductions about Greek aesthetic preferences, genitaliawise (here I mainly follow Kenneth Dover's landmark study Greek Homosexuality, 1978): (1) Long, thick penises were considered — at least in the highbrow view — grotesque, comic, or both and were usually found on fertility gods, half-animal critters such as satyrs, ugly old men, and barbarians. A circumcised penis was particularly gross. (2) The ideal penis was small, thin, and covered with a long, tapered foreskin. Dover thinks the immature male's equipment was especially admired, which may account not only for the small size but the scarcity of body hair in classical art. A passage from Aristophanes sums up the most desirable masculine features: 'a gleaming chest, bright skin, broad shoulders, tiny tongue, strong buttocks, and a little prick.'"
- ↑ Ulrich Marzolph (2004). The Arabian Nights: An Encyclopedia, 97–8, Santa Barbara, Calif: ABC-CLIO.
- ↑ Partial concealment of the penis by the abdomen was noted in Paul Fussell's memoirs.
- ↑ "Men Worry More About Penile Size Than Women, Says 60-Year-Old Research Review". ScienceDaily. May 31, 2007.
- ↑ Education The Best Treatment For Penis Size Concerns
- ↑ (2006). Does Size Matter? Men's and Women's Views on Penis Size Across the Lifespan.. Psychology of Men & Masculinity 7: 129. Derived from data from Lever, J. (2003, June). The Elle/MSNBC.com sex and body image survey. Elle, pp. 111–113.
- ↑ Mundell, E.J. "Does Size Matter? Most Romantic Partners Say 'No'," MSN Health & Fitness: Men's Sexual Health, MSN.com, 27 May 2005. Retrieved 23 September 2006.
- ↑ E.J. Mundell (May 27, 2005). Does Size Matter? Most Romantic Partners Say 'No'. Forbes.
- ↑ (2008). The Barbie Mystique: Satisfaction with Breast Size and Shape across the Lifespan. International Journal of Sexual Health 20: 200.
- ↑ Eisenman R (2001). Penis size: Survey of female perceptions of sexual satisfaction. BMC Women's Health 1 (1): 1.
- ↑ Michael Pertschuk, Alice Trisdorfer. Men's bodies--the survey. Psychology Today. URL accessed on 2007-07-17.
- ↑ Jill Neimark. The beefcaking of America. Psychology Today Nov-Dec 1994 (web edition last reviewed 2004-8-30). URL accessed on 2007-07-20.
- ↑ Francken AB, van de Wiel HB, van Driel MF, Weijmar Schultz WC (November 2002). What importance do women attribute to the size of the penis?. European Urology 42 (5): 426–31.
- ↑ Size does matter (to gays). Mail&Guardianonline. URL accessed on 2006-11-09.
- ↑ The Happy Hook-Up: A Single Girl's Guide to Casual Sex. Alexa Joy Sherman, Nicole Tocantins. p208. Ten Speed Press, 2004.
- ↑ "Size queen" at gaylife.about.com
- ↑ 37.0 37.1 (2006). Does Size Matter? Men's and Women's Views on Penis Size Across the Lifespan.. Psychology of Men & Masculinity 7: 129.
- ↑ (1988). The relationships among height, penile length, and foot size. Annals of Sex Research 6: 231.
- ↑ Goodman FR (October 2002). Limb malformations and the human HOX genes. American Journal of Medical Genetics 112 (3): 256–65.
- ↑ Mortlock DP, Innis JW (February 1997). Mutation of HOXA13 in hand-foot-genital syndrome. Nature Genetics 15 (2): 179–80.
- ↑ Shah J, Christopher N (October 2002). Can shoe size predict penile length?. BJU International 90 (6): 586–7.
- ↑ Cecil, Adams The size of things to come. The Straight Dope. URL accessed on 2006-08-05.
- ↑ Bogaert AF, Hershberger S (June 1999). The relation between sexual orientation and penile size. Archives of Sexual Behavior 28 (3): 213–21.
- ↑ Research says erect gay penises are bigger. Salon.com. URL accessed on 2006-11-09.
- ↑ Does Penis Size Really Matter?. WebMD. URL accessed on 2006-08-04.
- ↑ Mascall, Sharon, “Time for Rethink on the Clitoris”, BBC News. 2006 June |url=http://news.bbc.co.uk/1/hi/health/5013866.stm
- ↑ "Cul-de-sac": Increase Her Orgasm. AskMen.com. URL accessed on 2006-09-22.
- ↑ 48.0 48.1 Questions and Answers about Sexual Anatomy. sexualtips.net. URL accessed on 2007-08-05.
- ↑ The Female Orgasm During Intercourse. WebMD. URL accessed on 2006-09-21.
- ↑ Dr. Chua Chee Ann, British Journal of Sexual & Marital Therapy Vol. 12, No 4, November 1997
- ↑ Does size matter. TheSite.org. URL accessed on 2006-08-12.
- ↑ do big penises hurt?. AskMen.com. URL accessed on 2006-08-14.
- ↑ The female reproductive system. birth.com.au. URL accessed on 2007-05-07.
- ↑ Facts about penis size. netdoctor.co.uk. URL accessed on 2007-05-14.
- ↑ Surgeons Pinch More Than An Inch From The Arm To Rebuild A Micropenis. URL accessed on 2007-07-25. "Whereas the average size of the human penis is around 12.5 cm or 5 inches, a micropenis spans less than 7 cm or just over two inches."
- ↑ (2009). Penis Size FAQ & Bibliography. Kinsey Institute.
- ↑ Length-boosting surgery for 'micro-penises'. New Scientist. URL accessed on 2006-08-06.
- ↑ Size decrease in Male infants with prenatal phthalate exposure. ehp. URL accessed on 2006-11-08.
- ↑ PCBs DIMINISH PENIS SIZE. URL accessed on 2007-04-09.
- ↑ Pesticides may affect penis size. London Free Press. URL accessed on 2008-04-07.
- ↑ Hormone Hell. DISCOVER. URL accessed on 2008-04-05.
- ↑ Lavender and Tea Tree Oils May Cause Breast Growth in Boys. NIH. URL accessed on 2008-04-07.
- ↑ http://www.petting-zoo.net/~deadbeef/archive/236.html
- ↑ http://ces.iisc.ernet.in/hpg/envis/maldoc104.html
- ↑ 65.0 65.1 Pelley, Janet (November 2008). Plasticizer may make boys less masculine. Environ Sci Technol.
- ↑ Rosenberg MJ, Waugh MS (July 1997). Latex condom breakage and slippage in a controlled clinical trial. Contraception 56 (1): 17–21.
- ↑ The Effectiveness of Condoms in Reducing Heterosexual Transmission of HIV
- ↑ Mondaini N, Ponchietti R, Gontero P, et al. (August 2002). Penile length is normal in most men seeking penile lengthening procedures. International Journal of Impotence Research 14 (4): 283–6.
- ↑ AIDS Health Care
- Bogaert AF, Hershberger S (June 1999). The relation between sexual orientation and penile size. Archives of Sexual Behavior 28 (3): 213–21.
- Eisenman R (2001). Penis size: Survey of female perceptions of sexual satisfaction. BMC Women's Health 1 (1): 1.
- EurekAlert! summary
- Goodman FR (October 2002). Limb malformations and the human HOX genes. American Journal of Medical Genetics 112 (3): 256–65.
- The Kinsey Institute penis size bibliography
- Kondo T, Zákány J, Innis JW, Duboule D (November 1997). Of fingers, toes and penises. Nature 390 (6655): 29.
- Lee PA, Mazur T, Danish R, et al. (April 1980). Micropenis. I. Criteria, etiologies and classification. The Johns Hopkins Medical Journal 146 (4): 156–63.
- Mortlock DP, Innis JW (February 1997). Mutation of HOXA13 in hand-foot-genital syndrome. Nature Genetics 15 (2): 179–80.
- (1983) It's Your Body: A Woman's Guide to Gynecology, 3rd, New York: Berkley Publishing.
- (1987). Race differences in sexual behavior: Testing an evolutionary hypothesis. Journal of Research in Personality 21: 529–51.
- Shah J, Christopher N (October 2002). Can shoe size predict penile length?. BJU International 90 (6): 586–7.
- (1993). The Relationships Among Height, Penile Length, and Foot Size. Sexual Abuse: A Journal of Research and Treatment 6: 231.
- Sutherland RS, Kogan BA, Baskin LS, et al. (August 1996). The effect of prepubertal androgen exposure on adult penile length. The Journal of Urology 156 (2 Pt 2): 783–7; discussion 787.
- Schonfeld, William A. (April 1943). Primary and secondary sexual characteristics: Study of their development in males from birth through maturity, with biometric study of penis and testes. Archives of Pediatrics & Adolescent Medicine 65 (4): 535–49.
- AltPenis.com What's Average?
- Documentary of Penis Pictures and Surveys Devoted to proving the penis is more than a size.
- Erection Photos — FAQ
- Penis Size FAQ & Bibliography An Kinsey Institute's information page on the penis.
- Penis Size Based on Body Parts
|This page uses Creative Commons Licensed content from Wikipedia (view authors).|