The process of freezing sperm and storing it for future use. Samples of semen are collected and checked under a microscope in the laboratory to count sperm cells and find out how healthy they are. The sperm cells are then frozen and stored. Sperm banking is often used for men who want to have children after having treatment that may cause infertility, such as certain cancer treatments. Sperm banking is a type of fertility preservation. Also called sperm cryopreservation.