Doctors in Edinburgh have performed a pioneering procedure to transplant a young man’s testicular tissue that was frozen before he underwent chemotherapy, in a potential breakthrough for male fertility preservation.
The trial procedure, carried out by NHS Lothian and underpinned by a decade’s worth of research from the University of Edinburgh, is the first of its kind in the UK and only the second reported worldwide.
The 19-year-old student, who wishes to remain anonymous, had testicular tissue removed and frozen in 2023 before undergoing a bone marrow transplant to treat a serious blood disorder.
The treatment, which involves high dose chemotherapy, can permanently damage the cells needed to produce sperm, leaving children who undergo it at risk of infertility in adulthood.
Three years after his treatment, tests showed that the patient had no sperm in his semen. In August 2026, doctors transplanted some of his previously frozen testicular tissue back into his body in the hope that it will begin to produce sperm.
He has recovered well following the procedure and will now be closely monitored. After eight months, some of the transplanted tissue will be removed and examined to determine whether sperm have been produced.
The procedure could eventually offer a way for boys who have had testicular tissue preserved before undergoing sterilising cancer treatment to have children.
Semen freezing is an established fertility preservation option for adolescent and adult males, but it is not available to prepubertal boys because they do not yet produce sperm.
As a result, there is currently no established clinical method to restore fertility in boys who face treatments that can cause permanent infertility.
Researchers at the University of Edinburgh have spent more than 10 years developing a clinical research programme to preserve testicular tissue from boys before they undergo potentially sterilising treatment.
The tissue contains spermatogonial stem cells, which are responsible for producing sperm from puberty onwards. By freezing the tissue before treatment, doctors hope that it can later be transplanted back into the patient and allow sperm production.
Professor of Developmental Endocrinology at the University of Edinburgh’s Institute for Regeneration and Repair, Rod Mitchell said: “This is a big step towards helping boys facing treatments that damage their fertility to have children of their own. Ten years ago, we started our research programme to freeze and store pieces of testicle from boys before they start chemotherapy, to preserve their fertility. 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.”