Uh, college and research texts now don't matter?
From nih.gov (just an example).
"According to the World Health Organization, sex refers to the biological and physiological characteristics that define men and women. Gender refers to the socially constructed roles, behaviors, activities, and attributes that a given society considers appropriate for men and women. While it is evident that biological differences, commonly referred to as ‘sex differences’, should be considered when prescribing medicines, it is unclear to what extent sociocultural differences, commonly referred to as ‘gender differences’, should be considered by the prescribing physician."