In a medical first for the United Kingdom, a 19-year-old patient in Edinburgh has undergone a transplant of his own testicular tissue that was frozen before he received chemotherapy. The procedure, which has been performed only once before worldwide, could open a new path for young men and boys to preserve their fertility before aggressive cancer treatments.
Rod Mitchell, professor of developmental endocrinology at the University of Edinburgh's Institute for Regeneration and Repair, called the development “a big step towards helping boys facing treatments that damage their fertility to have children of their own.”
The patient, who has not been named, received a bone marrow transplant in 2023 to treat a serious blood disorder. Before that treatment began, doctors removed and cryopreserved a sample of his testicular tissue, because the high-dose chemotherapy required for the transplant could permanently destroy the cells that produce sperm.
Three years later, tests confirmed that the patient had no sperm in his semen. In August 2026, surgeons implanted some of the previously frozen tissue back into his body, hoping it would resume sperm production, according to a statement from the University of Edinburgh.
“Fertility is something I've struggled with personally for a long time. I've always wanted to have children of my own but at some point, I found myself starting to slowly accept that that might never be possible for me,” the patient said after the transplant. “Having this procedure has given me genuine hope for the future.”
Over the next eight months, doctors will remove and examine small samples of the transplanted tissue to determine whether sperm have been produced.
Why freezing tissue matters
For adolescent boys and young men, freezing semen is an established method of fertility preservation. But prepubertal boys do not yet produce semen, leaving them with no option to safeguard their fertility before treatments such as chemotherapy or radiation.
Storing testicular tissue offers a potential alternative. The tissue contains spermatogonial stem cells, which normally begin producing sperm at puberty. The hope is that tissue frozen before treatment can later be returned to the patient, allowing natural sperm production to resume.
The Edinburgh testicular tissue project, launched in 2015 with support from Children with Cancer UK, has already stored tissue from more than 1,200 patients in the UK and over 3,100 worldwide for potential future clinical use.
“We are beginning to see some of these young men return to explore their fertility options. This study offers real hope for future fertility in boys facing cancer treatment,” Mitchell added.
Experimental but promising
The Edinburgh procedure is the first of its kind in the UK and only the second reported worldwide. The first transplant of frozen testicular tissue took place in Belgium in January 2025, when cryopreserved tissue was reintroduced into an infertile man who had undergone chemotherapy in childhood, after 16 years in storage.
Preliminary results from that case showed that dormant stem cells within the transplanted tissue revived and began producing sperm cells, a process known as spermatogenesis.
While the Edinburgh patient's outcome is still unknown, the procedure represents a significant step forward for fertility preservation in young male cancer patients. As research continues, it may eventually become a standard option for boys who currently have no way to protect their fertility before treatment.
