The circumference of a sexual partner's penis matters a lot to a woman when she has a one-night stand, according to an American study. Contrary to their claims, women pay minimal attention to their partner's penis size. Especially when it's a one-night stand. According to a study , unveiled at the Association for Psychological Science conference in San Francisco in May 2019, a woman prefers a man with a large penis for a one-night stand. To come to this result, a researcher from the University of California gathered 41 women. They had to handle 33 artificial penises, modeled using a 3D printer. The sizes of the different male sexes ranged from 10 to 20 cm in length and from 5 to 17 cm in circumference.