People who prefer to have sexual experiences with the sex other than the one to which they belong tend to project this as the norm for all people. There is a propensity to exploit those whose sexual experiences are preferably with members of their own sex. There is also an oppression of those of sexual orientation other than heterosexual, including failure to acknowledge their existence. This tends to be based on the heterocentrist belief that heterosexuality is somehow superior to, or more "normal" and "natural" than, homosexual relations.