Fertility preservation · 3 min read
Sperm freezing — or sperm cryopreservation — is the simplest and longest-established form of fertility preservation. Sperm has been successfully frozen and used in pregnancies for more than 70 years, and it remains one of the most reliable ways to protect future fertility.
Once frozen, sperm can be stored for many years and later used in treatments such as intrauterine insemination (IUI), IVF, or ICSI. Since 2022, UK law allows sperm, eggs and embryos to be stored for up to 55 years in renewable 10-year blocks.
A sperm sample is provided at the clinic, then assessed in the laboratory for count, motility and morphology. The sample is mixed with a cryoprotectant — a fluid that protects the cells — and then cooled to around −196°C in liquid nitrogen, where it can be stored safely for decades. Multiple samples are usually frozen so that enough sperm is available for future treatment.
The NHS recognises sperm freezing for people who are about to start treatment that may affect fertility (such as chemotherapy, radiotherapy or certain surgeries), people with a declining sperm count, trans and non-binary people before gender-affirming treatment, and those at risk of injury or working in environments where future fertility could be affected. Some people also choose to freeze sperm before a vasectomy, or simply for peace of mind.
The HFEA notes that sperm freezing is a well-established technique with no evidence that long-term storage harms sperm quality. Once thawed, some sperm cells will not survive — which is why several samples are usually stored, and why ICSI is often used so that even a small number of healthy sperm can achieve fertilisation.
For most men, sperm freezing is straightforward, low-risk and quick to arrange. A consultation is the best way to understand timing, storage and whether it suits your situation. You can read more about how we work on our treatments page.
