Color is associated with gender information (e.g., red-female). This study aimed to investigate whether the color red could influence the categorization of human bodies by sex. Visual stimuli were created using body silhouettes with varying along the waist-to-hip ratio from female to male perceptions. These stimuli were presented in conjunction with red, green, and gray colors, which were used either as body color (Experiment 1) or background color (Experiment 2). Participants were instructed to categorize the sex of the body stimuli as either male or female by pressing labelled keys. The results revealed that the color red had distinct effects on body perception, contingent on its role as a body color or background color. Specifically, when used as a body color, red induced a feminine body perception, whereas as a background color, it leaned towards a perception of masculinity. These findings highlight the significance of color cues in shaping gender-related body bias.