If homosexuality did not exist, and there were no sexual variants other than heterosexual, how would you know you are straight?

This is a question about opposites of self and how we as humans rely upon our opposites to create self-identity.

Do we need opposites of ourselves in terms of personality, socioeconomic status, appearance, sexuality, beliefs, feelings, etc etc in order to determine who and what we are? If so, how and why? In not, then what?

Topics: psychology, sociology, personality, mirrors, sexuality, opposites, self-identity