In a workplace discrimination case, is there a need to prove bias to prove discrimination?

In regards to workplace discrimination (one employee feeling he/she is being treated unfairly), is it required to prove a specific bias (he/she is being discriminated on the basis of their race, religion, sex, etc.)? Can you just prove a case or multiple cases of unfair or unequal treatment?|||Overt bias, or intent, is not necessary. Policies or practices that unintentionally impact a protected class are also discriminatory. But it is necessary to prove the impact on a protected class (e.g., race, gender, disability, etc.)|||Yes you have to prove that the unfair treatment is because of race, religion, sex, etc. There is no law against unfair treatment if they just don't like you.|||If you have been singled out because of your race, creed, religion, national origin, gender, age (if you are over 40), you may have a case. The magic word here is "singled" out. And, oh, yes, you would need to prove it.