Germ cells, which are diploid, undergo meiosis to produce haploid gametes. A gamete is a cell that fuses with another to form a zygote, which develops into an embryo. Female gametes are called eggs, while male gametes are known as sperm.
Sexual reproduction creates genetic variation in two ways: by shuffling together the chromosomes of parents, which happens during fertilization, and by recombining the genes on the chromosomes themselves, which happens during meiosis. Meiosis has two phases: I and II. In meiosis I, the germ cell's DNA recombines and produces two diploid daughter cells. In meiosis II, those diploid daughter cells divide to produce four haploid cells in total.