The Boys Who Lost Fatherhood Before They Understood It
A boy diagnosed with cancer at seven years old is not thinking about fatherhood. His parents are not thinking about it either, not really, not while they are absorbing a diagnosis and bracing for treatment. And yet, tucked into that first wave of decisions, is one about a future so distant it barely feels real: whether to try to preserve his fertility before treatment takes it away.
I recently completed a DPhil in reproductive science, alongside a master's in clinical embryology, focused on developing laboratory techniques to help preserve and restore fertility in prepubertal boys undergoing cancer treatment. Much of that work was spent in a lab, not with patients directly, but the more time I spent on the underlying science, the more I found myself thinking about the boys and their families behind it, and what they must be going through. That is what led me to write this piece.
The clinical process for preserving a child's fertility is careful and well established, but what happens emotionally, for the child, and later the adult he becomes, is rarely part of the conversation. I want to bring that gap into view and make the case that the mental impact of this experience deserves as much attention as the science trying to solve it.
The Clinical Picture
When a child is diagnosed with cancer, saving their life is the priority, but for many, the treatment that saves them can also take something else, their fertility. Chemotherapy and radiotherapy work by targeting cells that divide quickly, which is exactly what makes them effective against cancer. Unfortunately, the cells responsible for producing sperm later in life, called spermatogonial stem cells, also divide rapidly, and are often destroyed or damaged as collateral in the process. Depending on the drugs and doses used, this can leave a child with reduced fertility, or none at all.
Advances in cancer research mean childhood cancer survival rates have climbed dramatically in recent decades. In high-income countries, around 80% of children diagnosed with cancer are now cured. That is, rightly, one of medicine's great success stories.
But it also means that a growing number of people are living long lives after treatment and having to reckon with what that treatment left behind, including their fertility. For teenage boys and adult men, there's a straightforward answer: freeze sperm before treatment starts, the same way it's done for many adult cancer patients. But for a boy who hasn't yet gone through puberty, that option doesn't exist. The body hasn't started making sperm yet, so there's nothing to freeze.
Currently, the only options for these patients are still under experimental development: a small biopsy (a medical procedure that removes a small sample of tissue, cells, or fluid from the body) of testicular tissue is removed under anaesthesia and frozen, in the hope that by the time the child grows up, medical science will have found a way to use it to restore fertility. These options include generating patient-derived sperm within a lab or transplanting the biopsies back into the patient once they reach adulthood. The UK's first programme for freezing tissue biopsies began in 2002, and it now happens at a handful of specialist centres, working with a team of paediatric oncologists, reproductive specialists, psychologists, and genetic counsellors all involved in the decision. Families are told clearly: this is experimental. There is no guarantee it will work. It's a biopsy taken on hope, stored for a future that hasn't arrived yet but is on the horizon.
This is the gap my own research sits in, trying to build the lab techniques that could one day turn that frozen tissue into something usable.
The Psychological Gap
What strikes me most, working in this field, isn't the biology. It's the timeline. A five-year-old having testicular tissue frozen has no concept of fertility, parenthood, or what any of this means. The decision is, thus, made entirely by parents and clinicians, guided by careful, compassionate counselling, but the child himself isn't in the room in any meaningful sense. He often can't consent (it is his parents who provide consent) to what's happening to his body, and he won't understand the weight of it for years, sometimes decades.
That creates a very particular kind of delayed grief, one of the many late effects of cancer that surface long after the treatment has ended. Unlike an adult diagnosed with cancer, who processes the loss of fertility alongside the diagnosis itself, a boy who has this procedure as a child often doesn't confront what it means until adolescence, or later, when a friend becomes a parent, when a relationship gets serious, when the question "do you want kids one day?" stops being hypothetical. Research on childhood cancer survivors backs this up: many say they want biological children later in life, and infertility has been linked to lower self-esteem, and strain in relationships as adults, not necessarily because of the medical facts, but because of what those facts mean for identity, masculinity, and the future they'd pictured for themselves. The distress associated with infertility is not minor. Studies have linked infertility-related stress to depression and, in some cases, suicidal thoughts, and this burden on men specifically has historically received far less research attention than it deserves.
And there's very little structured support for that moment. The clinical process, the biopsy, the counselling, the freezing, is well established. What happens fifteen years later, when a young man learns what was done for him as a child and has to make sense of it, is a conversation the healthcare system isn't always equipped to have. That's the part of this story that doesn't often get told alongside the science.
Closing the Gap
The pace of progress in reproductive science gives real reason for hope. Techniques like the ones I work on are edging closer to turning tissue that has sat frozen for years into a genuine path to fertility, and that horizon is closer than it was even five years ago. But the science alone is not enough. Behind every frozen biopsy is a child who did not necessarily choose this, and later, a young man carrying the emotional weight of a decision made before he could understand it. As the medicine improves, we need to improve alongside it, building the emotional support these patients need, and making space for voices that are rarely asked to speak.
