Johnson and Tassinary (2005) proposed that visually perceived sex is signalled by structural or form cues. They suggested also that biological motion cues signal sex, but do so indirectly. We previously have shown that auditory cues can mediate visual sex perceptions (van der Zwan et al., 2009). Here we demonstrate that structural cues to body shape are alone sufficient for visual sex discriminations but that biological motion cues alone are not. Interestingly, biological motions can resolve ambiguous structural cues to sex, but so can olfactory cues even when those cues are not salient. To accommodate these findings we propose an alternative model of the processes mediating visual sex discriminations: Form cues can be used directly if they are available and unambiguous. If there is any ambiguity other sensory cues are used to resolve it, suggesting there may exist sex-detectors that are stimulus independent.