The naked truth is that discrimination costs us in productivity.  If I'm an owner or executive director, I want everyone fully involved.  I don't want anyone feeling like they're not being listened to, or are being passed over for jobs.  I want pathways to ideas and leadership open to all talent, irrespective of irrelevant considerations of appearance.  I want them fired up and feeling fully engaged and excited about our work. 

Some would say "bias is just perception, and often false perception."  I would say: perception is truth in this case.  When people FEEL like they are being treated unfairly, a few of them will respond by working that much harder to prove themselves.  But many will start to check-out, complain behind your back, and feel justified in giving less, because they feel they're getting less.

So, what do we - especially managers - do to keep everyone in the game?  Four things:

Examine our own thinking, and our hidden biases, and root out those biases.  Workplace culture follows leaders.  If we think and speak and act in ways that promote diversity, people will follow.  I know I have negative thoughts about some "different" people, because I live in a culture that creates that noise.  I don't ask for those thoughts but there they are, so I have to catch them and choose to set them aside as irrelevant and unhelpful. 
Clearly and frequently articulate that "diversity is in" and discrimination is unacceptable.
Proactively ask others whether they feel included and engaged and whether opportunities are fairly given.  You can build your own (free) surveys easily with sites like www.surveymonkey.com, but I strongly recommend the use of diversity trainers who can help you work with the data.
Finally, we need a totally different attitude than our typical right-wrong mentality.  Instead, we need to seek first to understand.  I may say something with the best of all intentions, yet someone could have been deeply hurt, or "heard" a message I never intended.  If my culture is safe enough for them to talk to me, and if I listen well, I can hear that they were hurt and learn in the future.  And by listening to me, they can understand what I really meant.  Both perceptions are real.  Neither was "right" nor "wrong" in the first case.  The more hospitably we share ideas, and the more powerfully we seek to listen and learn, the more we can create a shared reality that works for both or all. 

You get everyone fully in the game, when you

Lead with your best self.