When it comes to one night stands, penis size does matter.
According to a recent study, women are more interested in the girth of a casual lover's penis, than the length.
Forty-one women were asked to examine penis models of varying sizes and choose which they preferred for a one-night stand and which they prefered for a long-term partner.
The penises, which were made on a 3D printer, came in 33 sizes - ranging from 4 inches long and 2.5 inches in circumference to 8.5 inches long and 7 inches in circumference.
Models chosen for casual sex had larger girths than those picked for long-term relationships, but length stayed the same.
On average women preferred 6.5 inch penises for one-night stands and relationships.
"They preferred larger-girth (but not longer-length) models for one-time partners than for longer-term partners," the researchers wrote.
"Women's sexual selection may help explain why human penises are unusually thick compared to other primates."
The study, which was presented at a meeting of the Association for Psychological Science, also found that women tend to overestimate the size of 3D-printed penis they had just looked at.
The second study gave women one of the penis models for 30 seconds. They were then asked to pick the same penis model 10 minuted later.
Researchers reveal that women tended to overestimate the size of the penis.
"For men who are considering surgery to increase their phallus sizes, maybe they do not have to after all, if women tend to overestimate" the size of a penis they've seen, Leung told Livescience.
The research was conducted at UCLA's Sexual Psychophysiology and Affective Neuroscience (SPAN) Laboratory.