We also report men who believe that they are more successful at mating gaze more at male chests than less confident men & that women do gaze at sexualized body areas of men, specifically the hips and groin

Widman, D. R., Bennetti, M. K., & Anglemyer, R. (2021). Gaze patterns of sexually fluid women and men at nude females and males. Evolutionary Behavioral Sciences, 15(4), 315–325. Nov 2021. https://doi.org/10.1037/ebs0000183

Abstract: Investigations of sexual fluidity have consistently found that women are more fluid than men. Several theories have been proposed to explain this sex difference. Two of these suggest that women are sexually fluid due to reproductive pressure from men. These theories suggest that women are fluid, in part, to satisfy male sexual behavior, either by engaging in and enhancing polygynous matings or allowing extrapair copulations for the men with those women the men’s mates select. This suggests that women, in their assessment of the attractiveness of other women, should assess female attractiveness as men do. The current study examined gaze patterns of heterosexual men and women while looking at nude male and female models. The results replicate the common findings that women are more fluid than men and that men gaze at the breasts of nude female models. We also report men who believe that they are more successful at mating gaze more at male chests than less confident men and that women do gaze at sexualized body areas of men, specifically the hips and groin. Finally, as hypothesized, more fluid women spend more time gazing at the breasts of nude female models, suggesting a male pattern of attractiveness assessment. 

Check also Widman, D. R., Bennetti, M. K., & Anglemyer, R. (2019). Gaze patterns of sexually fluid women and men at nude females and males. Evolutionary Behavioral Sciences, Sep 02 2019, https://www.bipartisanalliance.com/2019/09/gaze-patterns-of-sexually-fluid-women.html