An employer may not fire, demote, harass or otherwise "retaliate" against an individual for filing a charge of discrimination, participating in a discrimination proceeding, or otherwise opposing discrimination. The same laws that prohibit discrimination based on race, color, sex, religion, national origin, age, and disability, as well as wage differences between men and women performing substantially equal work, also prohibit retaliation against individuals who oppose unlawful discrimination or participate in an employment discrimination proceeding.