Bias is something that all people have. Originating in fear or issues of safety, it is part of what has kept humankind around so long — helping us to know when to run and when to stay. Bias can be conscious (I know I don't like green tea) or unconscious (I often order green tea, but for some reason I don't drink it). Unconscious bias is shaped by previous experiences, what we have learned, stereotypes of society, what we read, what we see on TV. There are countless influences on unconscious bias.
Read more about "The Challenge of Unconscious Bias".