Since the dawn of time, man has pondered: Is my penis big enough?
The latest penis comparison study, just published in the peer-reviewed journal PLOS ONE, is hoping to solve the riddle with the help of a 3D printer. Yes, in this provocative albeit very small study, researchers from UCLA and the University of New Mexico recruited 75 women ages 18 to 65 to come into a lab and not only visually assess various penis sizes but feel them.
The researchers printed 33 penis models, which all looked like bright blue dildos, for the women to evaluate. According to the authors, the penis models did not look like real-life penises because "women generally rate male nudes as less attractive than heterosexual men rate female nudes, so making the penis model more realistic might have provoked negative responses." (LOL.)
The researchers hoped to answer two major questions about penis size: Do women accurately remember penis size? And does penis size preference change based on what type of relationship a woman is looking for, short term or longterm?
The researchers first asked participants to fill out a questionnaire inquiring about their number of sex partners, whether penis size played a role in their relationships, orgasm frequency, pain during intercourse, and other deeply personal matters.
Next, the researchers handed each participant a blue penis model to inspect. Ten minutes later, she was asked to select the same model from among the other 32 other blue rods. This experiment was meant to explore whether women accurately remember penis size.
After the recall test, the women were asked to identify which penis models represented the average erect penis size of American men, and which they would prefer for a one-night stand versus a longterm relationship.
For the one-night stand, women were prompted with the question:
“Imagine you're single and you're out at a restaurant with some friends. You meet an attractive man who is also single. He seems kind, intelligent, funny, and has a great job. You are feeling sexually aroused. He says he's in town for a conference but he has to fly back home tomorrow afternoon. If you could spend only this one night with him, what size would you want him to be?”
For long-term relationships women were simply asked:
"What would be the ideal size for a husband or a serious, longterm boyfriend?”
Turns out the women were pretty good at recalling "penis size"—that is, in a simulated lab environment using 3D-printed blue rods instead of actual human penises. When asked to identify the correct model immediately after handling it, most of the women were able to locate it. After 10 minutes, about half of the women successfully identified it.
Notably, "participants slightly underestimated penis length after the recall interval, but were very accurate recalling penis circumference." Meaning, 10 minutes after handling a model, participants showed a slight tendency to chose a model smaller in length but not girth compared to the one they'd held. (That's right, guys—a woman might underestimate your length, but she'll remember the girth just fine.)
As for relationship preference, the women wanted a slightly larger penis for a one-night stand (6.4 inches in length and 5.0 inches in circumference when erect) compared to a longterm relationship (6.3 inches in length and 4.8 inches in circumference when erect).
The researchers believe there's an actual reason for this difference. Women, they say, are more comfortable orgasming in longterm relationships, so they may desire a longer, wider penis during a one night stand to stimulate more nerve endings in the vagina.
"[Women] might prefer a larger penis for short-term sex partly so the increased physical sensation compensates for the reduced psychological connection," theorize the authors.
However, bigger isn't always better in the long run because "vaginal intercourse always causes tears in the vaginal mucosa," write the authors, referring to tissues in the vagina, "so women might prefer a smaller penis less likely to stress their physiology for regular, long-term mates."
Both size selections—one-night stand and longterm mate—registered slightly above the average male's penis size as recorded in previous studies.
It's also worth noting that 27% of participants reported that "they had ended a relationship due, in part, to a mismatch between their penis size preference and their partner’s penis size."
While the study was an interesting exercise in memory, we can only extrapolate so much based on a woman's behavior in a simulated, decidedly nonsexual environment. It's entirely possible that feeling very attracted to someone and being in the heat of the moment may affect women's perceptions of size as well. Further research is definitely needed.
The takeaway, for now: Size might matter for some women, but only a little bit.
Taryn Hillin is Fusion's love and sex writer, with a large focus on the science of relationships. She also loves dogs, Bourbon barrel-aged beers and popcorn — not necessarily in that order.