Prause, N., Park, J., Leung, S., & Miller, G. (2014). A new method using 3D-printed stimuli: Women's accuracy and preferences for different penis sizes. manuscript under review.
33 models used in psychological studies of women's penis size preferences. Norms are provided in the study cited above.
German public television (der Spiegel) reviewed the study:
Printed in "navy wool" to avoid suggestive skin tones, as penis size is known to vary by ethnicity.