Germ cells undergo meiosis. Germ cells are found in the male and female gonads and form sperm and eggs. Meiosis produces haploid gametes, which contain only one set of chromosomes, instead of diploid somatic cells, which contain two.
Meiosis is necessary for sexual reproduction, which allows for greater genetic variation in a species. Single-celled organisms that reproduce by mitosis produce two identical daughter cells. Genetic variation only occurs by spontaneous mutations in the organism. By contrast, organisms that reproduce using sexual reproduction combine two sets of genetic material, one from the male and one from the female, to form offspring that are genetically distinct from their parents.