An autosome is a chromosome that isn't a sex chromosome – that's to say there are an equal number of copies of the chromosome in males and females. For example, in humans, there are 22 pairs of autosomes, but the X and Y chromosomes are sex chromosomes. Human chromosomes Female (XX) Male (XY) The are two copies of each autosome (chromosomes 1-22) in both females and males. The sex chromosomes are different: there are two copies of the X chromosome in females, but males have a si… (More on Autosome)