Larger penises can indicate high attractiveness and good fighting skills, new Australian study reveals

A new Australian study has found a man’s penis size can reveal a lot about him, as people with larger phalluses are found to be more attractive and more intimidating to rivals. Researchers at the University of Western Australia joined ANU, Monash University, and the University of Melbourne in a new study designed to identify why human penises are so unusually large for our body size when compared to other primates. Lead author Forrest Research Fellow Dr Upama Auch, who works at the UWA’s Centre for Evolutionary Biology, said biologists have long debated why the appendage is so disproportionate for our body. The PLOS Biology study used 343 anatomically correct computer-generated male figures that varied in height, body shape, and penis size. More than 800 men and women were shown life-sized projections of these figures in-person or completed online surveys to test if penis size really did have an impact on a man’s sexual attractiveness. Results from the study found participants viewed penis size as an important factor in determining a man’s attractiveness and fighting ability. “A larger penis made a man more attractive to women and perhaps more surprisingly, we also found that men use penis size to judge both a rival’s attractiveness and his ability to win fights,” Dr Aich said. “Men rated rivals with a larger penis as being more physically threatening and more sexually competitive.” The results also highlighted that female choice and male-male competition have jointly favoured the larger penis size seen in humans. However, female attractiveness seems to be the stronger driving force behind penis size evolution in humans. Co-author Emeritus Professor Michael D Jennions, from the Australian National University, said while larger penis size increased male attractiveness to women and signalled perceived fighting ability, the effect of penis size on attractiveness to women was four to seven times higher. “This suggests the enlarged penis of humans evolved more in response to its effect as a sexual ornament to attract females than as a badge of status used by males, although it does both,” Professor Jennions said. The study also found that male attractiveness is not only dependent on someone’s manhood —with the study seeing how both body shape and height work with penis size to determine male attractiveness. A larger penis provided a weaker benefit to smaller, more pear-shaped men, Dr Aich revealed. “We measured how fast participants reacted to figures and they were significantly quicker to rate figures with a smaller penis, shorter height and a less V-shaped body as unattractive,” Dr Aich said. “This suggests that these traits are subconsciously almost instantly rated as less sexually attractive and physically threatening.”