Sperm can be stored over either the short or the long term. Various short-term storage and transfer devices are used to handle sperm in preparation for testing of fertilization procedures, but these processes are not suitable for storing samples for longer periods of time. Sperm degrades rapidly at warm temperatures, and long-term sperm storage requires the use of cryogenic technology.
For the short term, successful sperm storage requires only the use of basic medical procedures. Samples are collected in sterile containers, and those containers are transported rapidly to laboratories or operating rooms, depending on whether they are to be used for testing or fertilization purposes. In some rare cases, sperm may be processed and filtered while in transit to prevent the transmission of human immunodeficiency virus (HIV) or for some other medical purpose. Samples may be processed immediately or stored in refrigerated containers for a short period of time.
True sperm storage requires the use of sophisticated cryogenic technology. Extremely cold temperatures, which are typically achieved through the use of liquid nitrogen as a cooling agent, are able to entirely stop biological activity within cells, essentially freezing them in time. Long-term sperm storage makes use of this technology to freeze samples of viable sperm which can then be thawed for use years, or even decades, later.
Careful monitoring of the freezing process is essential for proper sperm storage. Improper freezing can lead to the formation of ice crystals and damage within cells which will make sperm nonviable. Proper freezing ensures that sperm is rapidly cooled from normal temperatures to the temperature of liquid nitrogen and then kept constantly at that temperature.
One major purpose of sperm storage is to preserve sperm samples for individuals who must undergo medical procedures that might damage their fertility. Cancer treatments commonly fall into this category, as do certain surgical procedures. Sperm may also be stored by men who choose to undergo vasectomies, so that they retain the option of having biological children at some later date.
Sperm may also be stored in sperm banks for use by women who wish to become pregnant but do not have fertile male partners. These storage facilities typically offer both anonymous sperm and sperm linked to particular known donors. Many sperm banks offer the chance to purchase a sample of sperm from a particular donor and then store most of that sample while some portion is being used for fertilization treatments.
