How does the production of gametes and sexual reproduction increase genetic variation

Sexual reproduction provides genetic variation because the sperm and egg that are produced contain different combinations of genes than the parent organism. Sexual reproduction involves meiosis which is the process of a cell doubling its DNA, shuffling its genes and then dividing the shuffled DNA among four cells.

Each resulting cell, or gamete from meiosis has only half the amount of DNA as the parent cell. So in order to form a new organism, two gametes, sperm and egg, must fuse, further mixing the genes to produce more genetic variation.