A new study has revealed that women prefer a slightly larger penis in a one-time sexual partner compared to a long-term partner.

Researchers from the University of California and the University of New Mexico provided women with 33 different-sized 3D penis models made of rigid, odorless, blue plastic (they were blue “to minimize racial skin-color cues”) to choose from. In total, 75 women, ages 18 to 65, took part in the study.

When asked to select the model which represented their preferred penis size in a long-term partner, the average response was 6.3 inches (16cm) in length and 4.8 inches (12.2cm) around. For a one-time sexual experience, the average plastic penis the women chose was slightly larger – 6.4 inches (16.3 cm) long and 5.0 inches (12.7cm) in circumference.

Previous studies had presented women with 2D, flaccid penises, so this is the first research to provide hard evidence that women’s ideal penises are slightly larger than average penis size.

The women in the study chose penises that were, on average, larger than those on supply. The average erect penis is 5.2 inches (13.1cm) long, and 4.6 inches (11.7cm) in circumference, according to a global analysis of 15,000 phalluses published last year. The interactive below, created by Nick Evershed, allows you to explore those averages.

Sexual psychophysiologist Dr Nicole Prause and a team of researchers also gave the women a questionnaire about their past sexual experiences. Their responses revealed a diversity of first-hand penis encounters, ranging from 2.5 inches in length to 8 inches. Some women also said that they had ended a relationship partly because of their partner’s penis size – 7% of women said because their partner’s penis had been “too large”, and 20% said it had been “too small”.

In August, Dr Prause spoke to the Guardian about female pleasure as part of a video series Vagina Dispatches.