As ANOVA corrects for multiple comparisons, it is a more appropriate statistical test for these data. These t-tests are noted for full disclosure of the analyses conducted. This finding did not vary by the dimension length, circumference. Women attended one session in the laboratory during which they completed questionnaires about their sexual history and selected among 3D erect penis models to indicate their size preferences for one-time or longer-term partners.
Women tended to recall the size of the 3D models very well, only underestimating penis length. Women preferred a larger penis size especially a larger circumference for one-time partners as compared to long-term partners.
While this preference for a larger phallus is above the average penis size, it is only very slightly above the average. While most declined to identify a penis size most likely to carry an STD, women selected even larger phallus sizes as the most likely to be infected with an STD.
In fact, women were generally very accurate in identifying the same model at both immediate and delayed recall.
When they did make errors, they slightly underestimated model length. One possible explanation is that women care more about circumference, so they may attend to it more [ 63 ]. These data are generally consistent with Mautz et al. Their participants preferred phalluses 2SD above their estimated population-average penis size, whereas our participants preferred penises that were only a little above average. This difference may be due to their images depicting flaccid penises, whereas our models depicted erect penises.
Novelty itself contributes to pleasure [ 66 ], so seeking a more novel-sized penis may be consistent with a goal to pursue pleasure primarily in one-time partners. Women may prefer a smaller penis size in a long-term partner compared to a one-time partner for reasons of both physical comfort and a preference for less masculinity in a longer term partner [ 67 ].
The difference in pleasure motive is also suggested by genital physiology. A larger circumference might stretch the vaginal opening such that the deep structures clitoral crura and vestibular bulbs are more stimulated, and the clitoral glans is more stimulated by penis movement [ 68 ]. Also, the vagina is densely packed with pressure-sensitive mechanoreceptors that detect stretch sensations [ 69 ].
These appear finely tuned to detect variability in circumference, whereas the vagina is less sensitive to differences in other stimuli such as vibration or warmth [ 70 ]. Other studies also found that women prefer a relatively larger penis proportional to body size [ 31 ], especially with respect to circumference e.
Given that women typically experience more pleasurable and orgasmic sex in longer-term relationships [ 71 ], they might prefer a larger penis for short-term sex partly so the increased physical sensation compensates for the reduced psychological connection. In one notable exception, a preference for general body somatotype did not differ by the relationship duration [brief uncommitted versus long-term partners in 72 ]. A larger penis could contribute to infection risks, such that a larger penis on more risky one-time partners elevates risk.
A larger penis has been associated with higher infection rates amongst men who have sex with men [ 73 ]. Also, an increase in friction during intercourse from a condom is associated with the introduction of more bacteria into the vagina [ 74 , 75 ] and more vulvar erythema [ 74 ]. Finally, women report that condoms increase their experience of pain during intercourse [ 76 , 77 ].
Anything that increases friction during intercourse may promote genital injury, indirectly increasing infection risk. A larger phallus would increase friction relative to a smaller phallus.
These potential complications of a larger penis suggest why the human penis has not evolved to be larger. Individual differences among the women were not examined in relationship to their penis size preferences, although various female traits could interact with their sexual health risks.
For example, women with wider hips tend to have a higher proportion of one-time sexual partners [ 78 ]. Presumably, given the variability in vaginal size and tonicity, some women would experience more tearing with a larger phallus than other depending on the morphology of their particular vagina. Generating haptic stimuli was relatively cost-effective and simple.
Free software was available for generating print files. Also, the print files are shared online to allow exact future replications. Undergraduate research assistants were able to create and monitor the work flow. The 3D printer used is now widely, cheaply commercially available. Expanding this model into preferences pertaining to other domains, or even for other penis shape preferences, appears desirable.
As a first study using life-sized 3D models of erect penises to investigate preferences, some limitations exist. Models were not perfectly ecologically valid. They were blue to minimize racial skin-color cues. They were made with rigid, odorless plastic. They were a simplified dome-on-cylinder form rather than realistically shaped and textured. The male body was neither described nor portrayed.
There were also limitations of self-report approaches. Men and women appear to have actually become less approving of one-time sexual partners since [ 81 ], which may affect the preferences that they are willing to report regarding such partners. Also, a significant minority 15 of 75 of women chose not to report a preference for penis size in short and long term partners, but did answer both of the recall questions. Perhaps these women did not have a clear preference, consistent with weak penis size preferences reported in some previous studies [ 54 , 65 ].
This could be viewed as a strength, insofar as women did not feel compelled to answer in cases where they did not feel they had a strong enough basis to generate an answer. Another limitation is sexual inexperience among some participants. Fifteen women in our sample indicated that they had never experienced sexual intercourse. This inexperience could underlie some of the size preferences observed. For example, women generally anticipate more pain with their first intercourse than they actually experience [ 82 ], so they may show risk-averse penis size preferences for shorter length and thinner circumference than they may prefer with experience.
Less experienced women may also be less accurate in their size estimates. However, a follow-up analysis showed that having had sexual intercourse yes or no did not predict penis size preferences, arguing against this possibility. A related limitation is that the experimental protocol necessarily limited the sample size, and these women were recruited largely near a college campus. There may be other biases in the sample related to the recruitment method and sample size that were not identified.
There are several implications of these data for males interested in long-term female partners. Males with a larger penis may be at an advantage when pursuing short-term female partners. Furthermore, women tended to slightly underestimate the length of penis models after a recall delay.
Women may misremember specific partners penis attributes as smaller than they really are. Men dissatisfied with their penis size have historically benefitted more from counseling than from surgically increasing their penis size [ 83 ].
This may help explain why most men seeking surgical interventions for enlarging what they perceive to be a small penis actually have a penis that falls within a normal range [ 16 ]. Finally, 3D printing allows greater flexibility and complexity in stimuli and highly accurate replications.
This first use of 3D stimuli to assess preferences is promising. Increasing print resolution and animation will broaden the research applications with haptic stimuli. The authors would like to thank numerous research assistants at University of California, Los Angeles for their assistance with data collection. We also thank Ardershir Rahman for assistance with model design and printing. National Center for Biotechnology Information , U. PLoS One. Published online Sep 2.
Heather Hoffmann, Editor. Author information Article notes Copyright and License information Disclaimer. Competing Interests: The authors have declared that no competing interests exist. Received Feb 11; Accepted Jun This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
This article has been cited by other articles in PMC. Introduction Both men and women often have reported discomfort with the appearance of their genitals.
Materials and Methods Stimuli: The penis models Based on previous studies see above about the distributions of penis length and circumference, the average American erect penis length was estimated as 6 inches Open in a separate window. Fig 1. Sizes of printed models.
Fig 2. Penile Models. If your measurements are bigger than the smallest number in the "smallest number column" and smaller than the largest number in the "biggest numbers" column, you meet the definition of normal.
Standard deviations SD give information on the amount of variance in penis size in the population. If the standard deviation is low, you would expect most men to have penis and erection sizes close to the mean.
Likewise, if the standard deviation is high, there is a wide range of lengths. Using the information from the study, you can determine the upper and lower bounds of each. Notice that the difference between the larger and smaller numbers becomes greater as you add more standard deviations.
The average penile and erection length in a study of over 15, men in centimeters :. When men were asked what they thought was an average penis and erection size, their answers were pretty far off from what researchers found.
Most men believe that the average length of an erect penis is greater than If you go back to the table, you see that what most men think is average is actually in the "biggest numbers" columns. Why the discrepancy? If you asked a hundred men to measure their penis size and erection size, how would they do it? Would a self-confident man who feels he is well-endowed or a man who is anxious that he does not quite measure up be more likely to report their data?
If a man knew he would report his penis size and erection size, would he err on the generous or the conservative side with the measurement? It's the same situation as women comparing their looks to air-brushed models and feeling self-conscious every time! Men are taught that it is socially desirable to have a bigger penis and a larger erection, just like women think the air-brushed look is socially desirable.
Social desirability bias also contributes to inaccurate measurements. Overall, because men have been given inaccurate information, researchers found that most men underestimate the size of their penises compared to other men. This misconception can have serious implications for men seeking penile lengthening surgeries.
Researchers found that most men seeking penile lengthening surgeries, a risky surgical procedure, had normal penis sizes. This misconception can also lead to sexual anxiety, avoiding sex, and having problems with erectile dysfunction and premature ejaculation when they do have sex. A man's penis can come in different shapes, all of which are normal.
All penises have a shaft with a head that tends to be wider than the shaft. An erect penis may curve upward or downward. It may bend to the side slightly or be straight.
All of these shapes are normal. A thicker fat pad in front of the pubic bone, fluid retention, shorter ligaments, or complications after a circumcision can make the penis appear much smaller in some men. This is called a buried penis. If you have a buried penis, your penis is actually longer than it seems. Put your hard knowledge to the test against these 12 facts. Urinary tract infections UTI may be most common in women, but they can affect men as well.
We'll show you how to handle a UTI. Here's how to shop Viagra smartly. Various aphrodisiac foods may boost your sex drive and improve erectile concerns. Here are 7 foods and supplements that work like Viagra. Health Conditions Discover Plan Connect. Medically reviewed by Daniel Murrell, M. Flaccid vs. Read on to learn more about the flaccid penis. Does flaccid size affect erect size?
How to measure your penis. Why are some flaccid penises longer than others? Is it normal to hang on one side or the other? Is my penis normal? Instead, a better approach is to focus your time, energy and effort on improving the aspects of your sexual performance and appearance that you do have control over, from preventing hair loss and improving grooming to increasing your erection quality, and most importantly, taking care of yourself.
Have a conversation. Schedule a virtual visit with one of our certified healthcare providers to find out how you can get hard — and stay hard. This article is for informational purposes only and does not constitute medical advice.
The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
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