What is main difference between sex and gender

Sex refers to the biological differences between male and female bodies, such as chromosomes, reproductive systems, hormones, and physical characteristics. Gender, on the other hand, refers to the social, cultural, and psychological aspects of being male or female, such as identity, expression, roles, and expectations. Sex is typically assigned at birth based on physical characteristics, while gender is a more fluid and varied concept that can be influenced by a person's experiences and beliefs.