Physical and Visual Characteristics of the Neck Predicting Gender Perception

Background: The association between neck characteristics (physical and visual) and the perception of gender is unclear. This association is critical, especially when the perception of the speakers' gender is of interest, such as in transgender patients. This study was the first to provide basic empirical data on this association among cisgender men and women. Methods: The necks of 30 adult men and women were measured physically and then photographed and evaluated visually by a group of 10 judges. These judges also evaluated voice recordings of the same speakers. Another group of 124 judges rated the visual and auditory masculinity/femininity of the necks and the voices. Results: While most physical measures of the neck were larger for men, neck-length did not significantly differ between genders. A stepwise multiple regression model revealed that the single physical measure that consistently differed between genders was neck-girth (P < 0.0001). The single visual-appearance measure that consistently differed between genders was thyroid-protrusion (P = 0.0003). Neck-girth was the only physical characteristic that significantly correlated with gender differences in voice. Furthermore, the size of the thyroid prominence (ie, Adam's apple) was not associated with gender differences in voice. Conclusions: Neck characteristics (both physical and visual) are significantly associated with the perception of gender. While larger necks are typically perceived as masculine, neck-length is neither associated with gender nor with the speaker's voice characteristics. These findings highlight the importance of examining various physical and visual characteristics of the neck, when considering a feminization confirmation procedure for transgender patients.