Women work in offices, factories, banks and private corporations. Gender bias is the partiality shown towards either women or men in giving them jobs, positions, perks, salary, facilities or authorities.
Generally it is believed that women are not fit for certain type of jobs or other facilities. It is felt that women are suppressed from progressing. Generally it is thought that they are given leadership posts. This is called the gender bias.
The gender bias may be there and may not be there. It is highly situation dependent. It is not universal.