The general body shapes of female and male bodies both have significant social and cultural symbolism. Physical attractiveness is closely associated with traits that are considered typical of either sex. The body mass index ( BMI ), waist-to-hip ratio, and especially waist-to-chest ratio in men have been shown in studies to rank as overall more desirable to women. Wide shoulders, a muscular upper body and well-developed upper-arm muscles are all traits closely associated with masculinity , similarly to other specifics of the male sex, like beards . These traits are seen more sexually attractive to women and also associated with higher intelligence, good leadership qualities and better health.