Biological determinism refers to the idea in which your sex, or physical characteristics, determines both your gender expression and sexuality. Within this theory, people who have a penis will identify as male and like women and people who have a vagina will identify as female and like men (Stanford Encyclopedia of Philosophy). This viewpoint is problematic because sex itself is a social construct and should not be equated with sexuality and gender expression. Biological determinism inherently excludes queer people.   [Satveer]