A sperm bank is a specialized medical facility that collects, screens, prepares, stores, and distributes human semen for reproductive use. The entire process is strictly regulated by agencies like the U.S. Food and Drug Administration (FDA), which oversees the handling of human cells and tissues to ensure safety and viability for recipients. This controlled environment manages the biological risks associated with assisted reproduction. A donor sample undergoes several rigorous phases before release for therapeutic use in fertility treatments.
Donor Screening and Eligibility Requirements
The process begins with extensive screening, as only a small fraction of applicants are accepted. Donor candidates must fall within a specific age range, typically 18 to 39 years old, to ensure optimal sperm quality. This initial stage involves a thorough review of the donor’s personal and family medical history, often spanning three to four generations, to identify hereditary conditions or genetic disorders.
Prospective donors undergo comprehensive physical examinations and infectious disease tests. Mandatory screenings include testing for HIV-1/2, Hepatitis B and C, syphilis, chlamydia, and gonorrhea, with repeat testing required throughout the donation period. Genetic carrier testing is also performed to screen for recessive conditions such as Cystic Fibrosis, Spinal Muscular Atrophy, and certain hemoglobinopathies. Facilities also conduct psychological assessments and background checks to evaluate the candidate’s suitability for the long-term commitment of donation.
Sample Preparation and Cryopreservation
Once a donor is eligible, the collected sample moves immediately to the laboratory for processing. Semen analysis confirms the specimen meets minimum quality standards for motility, count, and morphology, as not all sperm survive freezing and thawing. The sample is then “washed” to concentrate motile sperm and remove seminal fluid, which can be detrimental if introduced directly into the uterus.
The concentrated sperm are mixed with a specialized cryoprotectant solution, which prevents cellular damage during freezing. Glycerol is the most commonly used cryoprotectant, often supplemented with agents like egg yolk or soy lecithin to stabilize the sperm’s cell membrane. The cryoprotectant reduces the formation of lethal intracellular ice crystals and lowers salt concentration within the cells. The prepared samples are divided into small, labeled aliquots, usually in plastic straws or cryovials, and frozen using a controlled, slow-cooling method before being plunged into liquid nitrogen.
Storage, Quarantine, and Quality Assurance
Following cryopreservation, sperm vials are transferred to specialized cryogenic tanks for long-term storage. They are maintained at the ultra-low temperature of liquid nitrogen, approximately -196°C (-321°F). At this temperature, the biological activity of the cells is halted, allowing the sperm to be stored for decades without degradation. The samples are not immediately available for use; they enter a mandatory quarantine period.
Regulatory bodies require this quarantine period, typically six months for anonymous donors, to ensure safety against transmissible diseases. The delay accounts for the “window period” of infectious agents, such as HIV, where a person is infected but may not test positive immediately. After the initial donation, the donor must return after six months for a final re-test for all relevant infectious diseases. Only once the re-test results are confirmed negative can the quarantined samples be released for distribution. Internal quality assurance checks are also performed by thawing a test vial to assess post-thaw motility and viability.
Distribution and Therapeutic Use
Once released from quarantine, frozen sperm vials are available for purchase by fertility clinics and individuals. Distribution involves specialized shipping logistics, using insulated, liquid nitrogen-charged dry shippers that maintain the ultra-low temperature during transit. Each shipment is accompanied by detailed documentation, including the donor’s eligibility status and a summary of all infectious disease testing performed.
The sperm is used in various assisted reproductive technology procedures. The most common application is Intrauterine Insemination (IUI), where thawed sperm is inserted directly into the recipient’s uterus around ovulation. Alternatively, the sperm may be used for In Vitro Fertilization (IVF), a complex procedure where the sperm is combined with an egg in a laboratory dish. The sperm bank also provides non-medical information, such as educational background and physical characteristics, to help recipients select a donor.