I have realized over a period of time that looks are important. Good looking people generally have a better deal in life.
People are more likely to listen to what good looking people have to say. In a job interview, a good looker is more likely to get the job.
I have also seen some newspaper reports of research that proves this.
All this, I believe is sub conscious. Unfortunately. If it was being consciously done (of course, there are cases where it is being consciously done, but that is not what I am referring to), it is relatively easier to correct. But if it is not being done intentionally, the individual being biased does not even know he/she is doing it.
And this has nothing to do with gender related attraction. A (straight) man is as likely to be biased towards a man as a woman.
I have myself experienced this many times. Many, in my office are biased towards better looking people at different levels.
I myself might have exhibited this trait some times. Again I'm not consciously aware of this but it is possible.
The mind, as I said before is amazing in many ways!