An employee who feels they are being sexually harassed or discriminated against shouldn't have to feel afraid to report this wrongful conduct to their supervisor or HR. But many do. Why?

In a word: retaliation. 

Workplace retaliation is about more than hurting an employee who makes an internal report of harassment or discrimination. It's about creating fear among all the other employees in the company. It's about making employees afraid to complain or assert their rights. 

And it's illegal.

An employer may not retaliate against an individual for opposing unlawful discrimination (based on any protected category, such as age, disability, gender, national origin, pregnancy, race, or religion) or for filing a charge of discrimination (with the Equal Employment Opportunity Commission or equivalent state agency), testifying, or participating in any way in an investigation, proceeding, or litigation under Federal or State discrimination laws.

Retaliation claims are based on any adverse action that your employer takes against you because you complained about harassment, discrimination, a health and safety violation, violation of accounting rules in certain larger corporations, or some other violation of a workplace law (such as overtime law). These laws also protect you if you are a participant in an investigation of any of these problems. For example, your employer cannot punish you for giving a statement to a government agency that is looking into another employee's discrimination claim, or a general workplace safety problem. All of this type of conduct is called "protected activity" and your employer may not retaliate against you for it.

The most common forms of retaliation involve claims of demotion, discipline, firing, salary reduction, negative evaluation, or changes in job assignment, however, they can also include hostility toward you by your employer.

Engaging in protected activity, however, does not shield an employee from all discipline or discharge. Employers are free to discipline or terminate workers if motivated by non-retaliatory and non-discriminatory reasons that would otherwise result in such consequences.  However, an employer is not allowed to do anything in response to protected activity that would discourage someone from resisting or complaining about future discrimination.