Sperm Frozen for Up to 12 Years: What Happened to Motility?

French researchers compared paired semen samples from 101 patients, including men with cancer.

Total motility fell by 3.6 percentage points in the 11–12-year subgroup, while overall changes were limited.

Across all samples, 84.6% retained the same assessed suitability for assisted reproduction.

Can sperm still be used to try for a pregnancy more than a decade after freezing?

Does a longer storage period reduce motility or damage fertilizing ability? These are understandable concerns for men banking sperm before cancer treatment and for couples preserving sperm for future fertility care.

A study reported that motility generally showed limited changes after storage for up to 12 years. Many long-stored samples retained the same assessed suitability for assisted reproductive procedures as shortly after freezing, adding evidence about the long-term stability of cryopreserved sperm.

Researchers from Clermont-Ferrand University Hospital and Université Clermont Auvergne in France published their findings in Andrology in October 2026.

What happens when sperm stored 12 years ago is thawed?

The researchers analyzed 101 semen samples banked for fertility preservation: 62 from patients with cancer and 39 from patients without cancer. Storage duration ranged from two to 12 years.

A key feature was the comparison of sperm from the same patient at different times. The team compared samples thawed shortly after freezing with samples thawed after long-term storage. They assessed total motility, progressive motility—the ability to move forward—and the number of motile sperm.

Sperm is generally stored in liquid nitrogen at approximately −196°C. At these extremely low temperatures, cellular metabolism effectively stops, allowing long-term storage. Freezing and thawing can nevertheless cause membrane damage or oxidative stress, making post-thaw assessment important.

Average changes in motility measures over two to 12 years were limited. The researchers did not find clear evidence that cancer status or the initial condition of the sperm substantially altered the pattern of change.

Longer storage alone therefore does not justify assuming that motility continuously deteriorates.

A 3.6-percentage-point decline after 11–12 years

Were there no differences even after more than a decade?

The researchers separately examined 24 samples stored for 11–12 years. Twenty-one were from patients with cancer.

Compared with the early post-freezing assessment, total motility decreased by 3.6 percentage points and the number of motile sperm fell by an average of 500,000. Both differences were statistically significant.

These decreases did not automatically mean the sperm was too damaged to use in fertility treatment. The researchers considered the changes relatively limited and suggested that their effect on the choice of assisted reproductive procedure might also be small.

However, the longest-storage subgroup contained only 24 samples, mostly from patients with cancer, limiting generalization to all men.

84.6% retained the same assessed treatment suitability

The study assessed not only motility but also whether samples remained suitable for assisted reproductive procedures.

Based on their post-thaw condition, samples were assessed for use in intrauterine insemination (IUI), IVF or intracytoplasmic sperm injection (ICSI).

Overall, 84.6% retained the same assessed suitability as at the initial post-freezing assessment. In the 11–12-year group, the figure was 87.5%.

For example, the researchers examined whether a sample initially considered suitable for IUI remained suitable for that procedure after long-term storage.

A modest decrease in motility therefore does not necessarily require a change in treatment method.

These percentages are not fertilization, pregnancy or live birth rates. Remaining suitable for a particular procedure and achieving a pregnancy with that sperm are different outcomes.

Relevance to fertility preservation before cancer treatment

The findings are particularly relevant to men facing cancer treatment.

Chemotherapy and radiotherapy can affect sperm-producing germ cells in the testes, reducing sperm production or causing permanent infertility. Banking sperm before treatment is therefore an important option for preserving the possibility of future pregnancy.

Cancer treatment and recovery can take time. Five, ten or more years may pass before someone has recovered and plans marriage or pregnancy.

The study provides evidence that sperm motility can remain relatively stable during such long periods of storage.

Sperm freezing is not limited to cancer care. It is also used for men who have difficulty producing a semen sample during fertility treatment, men with very low sperm counts, and men facing treatment or surgery that may affect reproductive function.

Preserved motility does not guarantee pregnancy. Sperm DNA damage, fertilizing ability and the potential for embryo development require separate assessment. This study did not directly establish pregnancy or live birth outcomes.

Nevertheless, it offers encouraging information for men and couples considering sperm banking. A long storage period alone is not a reason to assume that the sperm can no longer be useful.

What matters is a combined assessment of the sperm's condition when frozen, storage conditions, quality after thawing and the couple's reproductive circumstances—not simply the number of years in storage.

Freezing can pause sperm's biological activity without guaranteeing a future pregnancy. This study suggests, however, that the passage of many years does not by itself erase that possibility.

Study source

This article is based on “Sperm Motility Stability During Long-Term Cryopreservation: A Paired-Sample Study on 101 Fertility Preservation Patients,” published in Andrology in October 2026 by researchers from Clermont-Ferrand University Hospital and Université Clermont Auvergne. Authors include Cécily Lucas, Bruno Pereira, Laure Chaput, Jeanne Dufaure, Cyril Bouche, Florence Brugnon and Hanae Pons-Rejraji. They analyzed samples from 62 patients with cancer and 39 without cancer. DOI: 10.1111/andr.70414. PMID: 42885476.

The illustration was created using generative AI (ChatGPT, OpenAI). Any people depicted are fictional, not real individuals.