Gender interacts with but is different from sex, which refers to the different biological and physiological characteristics such as chromosomes, hormones and reproductive organs. Gender, on the other hand, refers to the range of characteristics pertaining to masculinity and femininity which are socially constructed. This includes norms, behaviors and roles associated with being a woman, man, girl or boy, as well as relationships with each other. As a social construct, gender varies from society to society and can change over time.