Genetic crossing over occurs during meiosis, which is a type of cell division that produces cells called gametes that are used for sexual reproduction. During meiosis, homologous chromosomes (chromosomes that carry similar genes) pair up and exchange genetic material, resulting in the shuffling of genetic information and creating genetic diversity. This process of exchanging genetic material between homologous chromosomes is called genetic crossing over. The end result of crossing over is the production of genetically unique offspring that have a combination of traits from both parents.