Meiosis: The process chromosomes undertake during germ-cell formation to halve the chromosome number from 46 to 23. In meiosis, the 46 chromosomes in the cell divide to make two new cells with 23 chromosomes each. Before meiosis is complete, however, chromosomes pair with their corresponding chromosomes and exchange bits of genetic material. In women, X chromosomes pair; in men, the X and Y chromosomes pair. After the exchange, the chromosomes separate, and meiosis continues.