In psychology, sex refers to the biological characteristics that differentiate males (XY chromosomes) from females (XX chromosomes). It includes physical attributes, reproductive systems, and genetic factors related to sexual development.
Related terms
Gender identity: An individual's deeply felt sense of being male, female, or something else.
Sexual orientation: A person's enduring pattern of emotional, romantic, and/or sexual attractions to men, women, both genders, or neither gender.
Intersex: Individuals who possess biological attributes that do not fit neatly into society's binary notions of male or female bodies.