"We found that male attractiveness is significantly influenced by penis size. More specifically, we found that large penises are rated as relatively more attractive than smaller ones," Dr Mautz said.
"Our results show that present-day females rate larger penises as more attractive, but it is hard to infer anything much beyond that. Part of the reason is because of clothing - it does complicate the situation," he said.
Unravelling the role played by the flaccid male member in making a man appear attractive to women was solved by using life-sized, three-dimensional images of naked male manikins projected on to a video screen.
Each of 49 different images was rotated slightly to show off the anatomically correct details of the male genitalia, while about 100 Australian women were asked to rate each life-size image according to its sexual allure, based on a score of one to seven.
In addition to varying the penis length, the scientists played around with the stature of the models, making the men appear taller or shorter, and with wider shoulders or hips, which were already known to influence male sexual attractiveness.
"The effect of penis size on attractiveness is not independent of the other two traits of height and shoulder-to-hip ratio. For example, penis size has a much larger effect on attractiveness for taller men, than it does for shorter men," Dr Mautz said.
"It certainly does show that size matters, at least on some level, and that how much it matters is relative to other traits."
- THE INDEPENDENT