Meiosis reduces the number of chromosomes so that gametes are haploid, or cells that contain only one set of chromosomes. In humans, there are over 8 million different genetic possibilities for each gamete we produce just from the independent assortment that occurs duringmeiosis.
Meiosis not only helps ensure that our offspring have the right number of chromosomes, it also contributes to that genetic variation we talked about before. During meiosis, cells are split so that genetic information is divided up into multiple gametes. The genetic information you got from your parents is randomly divided, and this random distribution of paternal and maternal chromosomes is called independent assortment.
There are an incredible number of possible combinations from independent assortment. The total combination of chromosomes for any species is 2^n, 'n' being the haploid number for that organism. So, for humans, who have 23 pairs of chromosomes (23 being our haploid number), there are 2^23 possible chromosome combinations. That's over 8 million different possibilities! And that's just your gametes! That means each gamete you produce has one of these 8 million combinations of genetic information that you got from your parents, but so does everyone else's. Of course, their genetic information came from their parents, but you can see how each individual contributes to a great amount of genetic variation.