You spend half your career being told that you are too young by prospective clients and investors (I was rather astounded when we were turned down on this ground at first, rather than anything to do with the product or service, but eventually grew to accept it), and then the next half being told you are too old by the same. Ah, to be forever 34 and eight months.
Whatever reason an investor gives for turning your investment down, it's actually code for "I don't think you can pull this off."
I would think bias is more likely to get eliminated the further up the funding ladder you go (i.e. sure this person might not look like me, but the numbers prove he knows what he/she knows what their doing).
However at the angel stage, there's so much room for subjectivity that I can't believe bias doesn't play a role.