By Laura Garrido BSc, MSc (embryologist).
Last Update: 09/07/2015

Semen freezing is a widespread procedure used to preserve male fertility. Once the sperm is analyzed, the sample is frozen. These samples are stored in a semen bank, where they can be kept for unlimited time until its use is required.

Sperm quality is barely altered by the freezing, therefore it can be used in assisted reproductive procedures to get pregnant.

The different sections of this article have been assembled into the following table of contents.

How does it work?

Semen freezing in based on blending the semen sample with a cryoprotectant, which is composed of egg yolk proteins, and slowly freezing the resultant mixture, lowering the temperature progressively until it is submerged in liquid nitrogen.

When to use frozen sperm

When required, the frozen sperm may be used for an artificial insemination or an in vitro fertilisation, according to the specific case. If the freezing is slow, the thawing process is fast and, in a few minutes, temperature rises from -196ºC to 37ºC. The process is 15 minutes long. From that moment on, the sperm can be processed and finally ready to be chosen in an assisted reproductive procedure.

If you are considering freezing your sperm to have a child in the future, we recommend that you start by creating a Fertility Report. In 3 simple steps, it will show you a list of clinics that fit your preferences and meet our strict quality criteria. Moreover, you will receive a report via email with useful tips to visit a fertility clinic for the first time.

Freezing formats

Freezing can be done in tubes, i.e. small rehearsal tubes with a capacity of 1 ml where the blend of the semen and the cryoprotectant rests, and in the first instance a slow freezing by means of vapors of nitrogen is done. Afterwards, a second freezing with liquid nitrogen is done and the tubes are stored in sticks that string them.

The sperm is frozen in small pills when the semen is valuable, as in cases of HIV seminal lavage, or in a patient that freezes his semen before undertaking a chemotherapy treatment, making its delivery easier in case his semen is required for several cycles of in vitro fertilisation. In such cases, the semen is kept in properly labeled receptacles that are submerged in tanks of liquid nitrogen.


Cancer patients

Men that suffer from cancer and are set to be treated with chemotherapy and radiotherapy must preserve their fertility before undertaking these treatments, in case their wish is to be a father. Once they have overcome the disease, sperm production might be altered, or its quality decreased. After a while, there is a chance the sperm alteration could be reverted, but in most cases these drugs produce permanent male infertility.


Some patients decide to have a vasectomy as a contraceptive measure because they don’t want to have more children, but choose to save a cryopreserved semen sample as a precaution. Therefore, they still have the opportunity to become parents, either with the same partner or with a different one.

Some men experience difficulties when trying to ejaculate, and sometimes the issues come from tight schedule. Thus, if there is a preserved sample in the semen bank of the fertilisation clinic, the donor doesn’t need to be physically there when the woman starts the fertilisation treatment.

Sperms donors

Spanish legislation compels the clinics to conduct a series of tests to determine the semen is not polluted. These tests must be carried out months after the donation is done, being thereby necessary to freeze all the collected samples.

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Authors and contributors

 Laura Garrido
BSc, MSc
Bachelor's Degree in Biotechnology from the Pablo de Olavide University (UPO) of Seville, Spain. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). Experience at IVF, andrology, and general analysis laboratories. Embryologist specialized in Assisted Reproduction. More information
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One comment

    1. Nathan

      I find it marvelous that semen can be frozen… It’s a very advisable alternative to men suffering from testicular cancer, since it allows them be sure they will be able to be on fatherhood if they want to in the future. Who knows what the future holds?