Tuesday April 9 2013
The average erect penis is about 14-16cm (5.5-6.3 inches)
‘[Penis] Size does matter, study finds', The Daily Telegraph reports with almost identical headlines in the Daily Mail and The Independent.
The news is based on a study in which researchers asked a small group of women to rate the attractiveness of computer-generated images of naked men of various heights, body shapes and with different sizes of penis. The women were then asked to rate their sexual attractiveness on a scale of one to seven.
They found that males with a larger penis were rated as being more attractive, although only up to a certain size, and the finding applied more to taller men.
Before worried chaps starting popping blue pills or purchasing pressure pumps, it’s worth bearing in mind that this was a small study, and women were asked to rate attractiveness at a single point in time.
Computer-generated models are unlikely to reflect how attractive women really find a man in the flesh.
Where did the story come from?
The study was carried out by researchers from Australian National University, Monash University and La Trobe University, all in Australia, and the study was funded by the Australian Research Council.
The study was published in the peer-reviewed journal PNAS (Proceeding of the National Academy of Sciences).
The researchers say it is not clear whether penis size affects attractiveness when assessed along with other, arguably more important, body traits such as height or body shape.
The story was covered appropriately by the UK media, with The Independent taking a particularly tongue-in-cheek and hyperbolic approach.
Many internet-only news sources promoted the message as ‘it’s official!’ and ‘science has spoken’ that penis size ‘matters’. This reveals a disturbing lack of insight into how science works. A single study involving 105 women may add slightly to the body of evidence, but it certainly does not make something ‘official’. Very few things reach the status of ‘official’ in science.
What kind of research was this?
This was a survey carried out at one point in time, and the findings were analysed by the researchers to try and determine how women’s perceptions of male attractiveness vary depending on penis size in the context of different male body heights and shapes (shoulder-to-hip ratio).
The researchers say that novels, magazines and popular articles often allude to the relationship between penis size and sexual attractiveness or masculinity.
In contrast, there have been previous studies in which women have reported that penis size is of minimal or no importance when selecting a partner.
What did the research involve?
The researchers were interested in testing the effects of three main traits on women’s perception of male sexual attractiveness:
- flaccid (unerect) penis size
- body shape – specifically the shoulder-to-hip ratio, known to influence male sexual attractiveness
- height, also known to influence male sexual attractiveness
The researchers presented life size, computer-generated naked male figures to 105 heterosexual Australian women with an average age of 26 years. Each male figure was an animated video and the figure was able to rotate 30 degrees to each side to allow the women to more easily assess it.
The figures presented to the women each had different ‘traits’ that the researchers had manipulated to make the men appear shorter or taller and broader- or narrower-shouldered.
Each of the traits had several possible shapes and sizes that were considered within the normal ranges based on previous survey findings. Height ranged from 1.63 to 1.87 metres and penis length ranged from 5cm (2in) to 13cm (5.1in) – although the researchers do not explain where this is measured from (a common controversy).
The researchers noted that as part of the program used to generate the figures, penis width (girth) grew relative to the increase in penis length, and so the term ‘penis size’ was used throughout the research. Overall, there were 343 trait combinations that were possible as a result of varying each trait independently.
The researchers asked the women to view 53 randomly generated figures and asked them to, ‘rate each figure based on how sexually attractive they are to you’. The women were not informed of which traits varied and were only told that the study was on male attractiveness.
Included in the 53 images were four of the same figures that acted as controls and had the averages of all traits.
The researchers used these figures to determine whether women consistently assessed these figures the same. Attractiveness was rated on a Likert scale that ranged from 1 to 7.
Rating of the figures was anonymous and there was no interviewer in case they influenced responses. Traits of the women were also assessed to see if they had any correlation to the answers they provided.
The researchers then analysed the ‘attractiveness’ data appropriately to determine any interactions between the traits.
What were the basic results?
The main findings of this study were:
- penis size had a significant influence on women’s perceptions of male attractiveness
- males with a larger penis were rated as being relatively more attractive, however, the increase in attractiveness began to slow at sizes larger than around 7.6cm
- penis size had a stronger effect on attractiveness in taller men than shorter men. When the researchers controlled for body shape, larger penis size had a greater effect on attractiveness for taller men. The researchers say this may because penis size appeared smaller as height of a man increased or because of general discrimination against short men, regardless of their other traits
- height and shoulder-to-hip ratio also influenced a male’s relative attractiveness, with taller men and broader shouldered men rated as being more attractive by the women
- interestingly, the researchers say the ‘most attractive penis size’ appears to fall outside the ranges used in the study
How did the researchers interpret the results?
The researchers say in their conclusions that their results ‘directly contradict claims that penis size is unimportant to most females’.
Lead researcher Dr Brian Mautz, formerly from the Australian National University, is reported as saying, ‘We found flaccid penis size had a significant influence on male attractiveness. Males with a larger penis were rated as being relatively more attractive.’
The researchers conclude that the study findings support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. That is, men with genetic traits that predispose them to have a larger penis were more likely to reproduce so these traits become more prevalent in future generations.
Overall, this study provides limited evidence that male attractiveness assessed by women is influenced by penis size. First, this is a small study carried out among just over 100 heterosexual Australian women. The findings from this study are unlikely to be applicable to women of ages not included in this study or to women of different backgrounds or cultures.
Second, sexual attractiveness was rated using computer-generated images rather than real men. This may not have accurately captured whether a women does find particular traits sexually attractive should she be presented with them in the flesh.
Third, this survey was carried out at only one point in time, and it is possible that women’s perceptions would be different at different times in their lives.
Finally, most people would argue that there are far more important factors to having a good sex life than penis size, such as being receptive of your partner’s needs.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.