Man produces sperm from childhood-frozen testicular tissue after 16-year retransplant
Updated
Updated · The Guardian · May 4
Man produces sperm from childhood-frozen testicular tissue after 16-year retransplant
9 articles · Updated · The Guardian · May 4
The 27-year-old Belgian patient had tissue frozen at 10 before high-dose chemotherapy for sickle cell disease; two grafts in his remaining testicle later produced mature sperm.
Researchers at Vrije Universiteit Brussel called it the first human proof that cryopreserved prepubertal testicular tissue can restore sperm production, though the preprint has not yet been peer reviewed.
The sperm was frozen for possible IVF, while similar UK transplants are expected soon; more than 3,000 patients worldwide have banked tissue, including over 1,000 in Britain.
A boy’s tissue was frozen for 18 years. Can it now be used to safely create a healthy child?
After a medical first restored a man's fertility, what are the true odds of fatherhood for other survivors?
Pioneering Fertility Preservation: The 2025 Case of Testicular Tissue Retransplantation and Its Implications for Childhood Cancer Survivors
Overview
Since 2002, UZ Brussel has led the world’s first clinical program to preserve fertility in young cancer patients by cryopreserving testicular tissue. In 2010, a boy had his tissue frozen before chemotherapy, which was retransplanted in 2025 when he was 27. The procedure involved placing tissue fragments into the testicle and scrotum to encourage sperm production. Monitoring showed healthy grafts and normal hormone levels, but no sperm appeared in the ejaculate due to the grafts’ design, meaning assisted reproductive technologies will be needed. In 2026, the transplanted tissue will be examined to confirm sperm development. This milestone offers hope but fertility restoration remains experimental.