The combined effects of an aging population and a sluggish economy have led to an increase in lawsuits alleging age bias in the workplace. The Age Discrimination in Employment Act (ADEA) prohibits age discrimination in the employment of persons who are at least 40 years old. The ADEA covers most private employers of 20 or more persons. It forbids age discrimination in advertising for employment, hiring, compensation, discharges, and other terms or conditions of employment. Retaliation against a person who opposes a practice made unlawful by the ADEA or who participates in a proceeding brought under the ADEA is a separate violation.