An ER does not need a reason to fire an EE, even if you were the best EE in the place. The law allows businesses to have bad management, to act foolishly, to lie to EEs generally, and run their businesses into the ground if they so desire. So the answer to your question is "yes", with an exception. What the law does not allow is illegal conduct, e.g. terminating EEs because of their protected status or protected conduct. If you have "substantial evidence" that your termination was based on your race or national origin beyond the fact you were terminated and replaced by a White male, then you may have a case. You need something more than suspicion to go forward. I would suggest filing a claim with the DFEH that you believe you were terminated due to your national origin or race, and that you were replaced by a white male and see what the Company has to say. You may get the evidence you need that way because whatever they say you can prove it to be false. Just be prepared to wait as this takes some time.