Sex refers to a person's biological sex. According to the OMS, 'sex' refers to the biological and physiological characteristics that define men and women, while 'gender' refers to the socially constructed roles, behaviors, activities, and attributes that a particular culture considers appropriate for men and women. According to this description, the OMS considers 'man' and 'woman' to be categories of sex, while 'male' and 'female' are categories of gender.