Women Pick the Perfect 3D-Printed Penis

Using 3D-printed phalluses, researchers asked women to pick their “perfect” penis—one for a long-term partner and another for a one-night stand. Turns out, bigger isn’t always better.

09.02.15 6:50 PM ET

Forget about tissue engineering and chocolate sculptures. 3D printing has finally achieved its true purpose: helping scientists discover the size and shape of the perfect penis.

For the first time, a group of researchers from UCLA and the University of New Mexico have used 3D-printed phalluses to ascertain women’s penis size preferences. Previous studies on the subject have asked women to state a length in centimeters or to select “small, medium, [or] large,” as if they were ordering a side of french fries. Other experiments have presented women with 2D drawings, but what is a penis, really, without the third dimension?

The study—published today in the peer-reviewed journal PLOS One—contains good news for men: Women prefer a penis size only slightly above average, and their preferences differ slightly depending on relationship context.

To perform the study, sexual psychophysiologist Dr. Nicole Prause and her team generated a matrix of 100 different erect penises with varying lengths and circumferences but eventually narrowed them down to 33 options, reasoning that “such a large choice set could overwhelm participants.” These 33 representative choices were then 3D-printed in blue plastic “to minimize racial skin-color cues” and sorted into baskets from which 75 women selected an ideal penis for both a long-term partner and a one-night stand.

To ensure that the women’s choices were not arbitrary, the researchers also required them to complete a pretest in which they attempted to recall the shape of a randomly selected phallus, both immediately and after a delay. The subjects proved themselves adept at remembering penis length and especially skilled at recalling penis circumference, which may indicate that they “care more” about the latter measurement.

But enough methodological foreplay. Here is the size and shape of the ideal penis according to this sample of 75 women. For a long-term partner, the women reported an ideal length of 6.3 inches and an ideal circumference of 4.8 inches. For a one-night stand—described by the researcher conducting the experiment as a man who is “kind, intelligent, funny, and has a great job”—the sample indicated that 6.4 inches long and 5 inches around would be best.

Either way, the findings are good news for any man who thinks he needs to be extraordinarily well-endowed to find a sexual partner. The authors note that, “our participants preferred penises that were only a little above average.” For reference, the average American erect penis is estimated to be about 6 inches long with a circumference of 5 inches.

The fact that women’s preferences differ based on relationship context should also be reassuring, the researchers say.

“Since context matters, men should be thinking ‘fit’ rather than ‘fat’ with respect to their penis size,” Prause told The Daily Beast. “In other words, women may prefer different sizes for different reasons at different times, so chances are very good any guy is someone's ideal for the relationship type they are seeking.”

As for the motivation behind those different preferences, the authors speculate that women in search of a one-night stand might want a larger penile circumference because it enhances sexual pleasure, which, after all, is usually the goal of a casual encounter.

Women Pick the Perfect 3-D Printed Penis

Neal Preston

“To maximize the chances of receiving the sexual benefits it makes sense that women might prefer a larger girth penis that brings the clitoral glans closer to the friction point and also will stimulate the crura [“legs”] of the clitoris internally more,” Prause explained.

The use of 3D phalluses to discover this preference is not just novel, it may be the most effective way that ideal penis size has ever been measured. Many previous studies, the authors note, have “portrayed or asked about the penis in its flaccid state,” which seems counterproductive given the organ’s most desired function.

By presenting women with rigid models that could be examined and touched, the researchers were able to more closely approximate the circumstances of a sexual encounter—at least, as closely as handling a blue plastic penis in a controlled environment can allow. For a body part that is best experienced up close, the penis has too often been evaluated in the abstract.

“[H]umans judge sizes most accurately when visual and haptic information are available together,” the authors write, adding a little wryly that “both sources of data are usually available in sexual interactions.”

For men who are considering unproven penile enlargement techniques to supposedly enhance their own sexual interactions, the study offers some levelheaded reminders. The authors note that men who are anxious about their penis size have previously reported an ideal length that is longer than women actually want. Additionally, most men who undergo penile enlargement surgery “actually fall within the normal penis size range.”

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It’s not that penis size doesn’t matter at all—this study, among others, is proof that it does—but many men’s hang-ups with it may be overblown. It is true, for example, that 15 of the women in the study said that they had ended a relationship, in part, because of a small penis but five of them also cited a too-large penis as a contributing factor in a breakup.

“There is a cost with a larger phallus,” Prause told The Daily Beast. “All intercourse causes tearing and pushes bacteria into the vagina. A larger phallus probably causes more tearing and may push more bacteria into the vagina: not a good long-term option.”

And Dr. Geoffrey Miller, a co-author on the study, wants men to know that size isn’t everything.

“Human penises evolved to be unusually long and thick, consistent with our findings about women’s preferences,” he wrote in a press release accompanying the study. “Yet a man’s intelligence, kindness, sense of humor, and other mental traits are also extremely important to women.”

The takeaway for women is a bit more physical. For once, this is an experiment that you can try at home. Dr. Prause has uploaded all 33 blue phallus models used in the study to the design sharing website Thingiverse where they can be downloaded for free, printed out, and placed in your very own basket full of penises.