The process of freezing sperm is safe and consistent, according to Dr. Guarnaccia, and typically follows these steps:
Step 1: After an infectious disease screening that checks for sexually transmitted diseases, a sperm specimen is collected by the person wishing to freeze their sperm via masturbation, either at home or at a fertility clinic. If the specimen is collected at home, it must be delivered to the lab as quickly as possible or within a few hours.
Step 2: The sperm specimen is analyzed with a microscope to determine the amount of semen or liquid ejaculated, the consistency of the ejaculated fluid, the actual number of sperm—this is referred to as the sperm count—and how the sperm is moving (this is referred to as motility).
Step 3: Depending on the sperm analysis results, the specimen may be divided into one to three vials, and each vial is then mixed with a cryoprotectant solution that protects the sperm. Cryoprotectants are designed to replace the water that is normally in the sperm cell, so it prevents ice crystal formation from occurring once the sperm is frozen. Because ice crystal formation can damage the sperm membrane, cryoprotectants play a key role in keeping them intact.
Step 4: At this point, the specimen undergoes a controlled drop in temperature in a freezer with long-term storage in a liquid nitrogen tank at -196 degrees Celsius. This is the final step and freezes the sperm for storage. The total length of time sperm can be frozen for is unknown, but Dr. Guarnaccia says that theoretically, they could be frozen forever. “Sperm cryopreservation was introduced in the 1960’s and the sperm can theoretically stay frozen indefinitely under properly maintained liquid nitrogen storage conditions,” he says. “Pregnancies have been reported from sperm frozen 30 to 40 years ago and utilized in both IUI and IVF/ICSI procedures.”
If you’re considering freezing your sperm, Dr. Guarnaccia adds you’ll want to start by contacting either a fertility specialist or urologist. “Additionally, some men may choose to contact a sperm bank directly, and they will be guided through the process, including any testing they may need before producing and freezing a specimen,” he says.