Sex is biological and physiological characteristics, such as chromosomes, reproductive organs, and hormones – which are either male or female. 

Gender refers to socially constructed roles, behaviors, and identities that are influenced by social, cultural, and personal experiences. It may also refer to how society responds to an individual based on their gender presentation 

Sexuality is different. By definition it’s a person's identity in relation to the gender or genders to which they’re attracted or choose to live as.