Can my child have children — fertility after childhood cancer

This is one of the most important questions parents ask, and you deserve a straight answer: many childhood cancer survivors do go on to have children of their own. Whether your child will be fertile after treatment depends on several things — the type of cancer, the treatments used (particularly which chemotherapy agents and whether radiation was given near the reproductive organs), the dose received, and your child's age and stage of development at the time of treatment. Some children complete treatment with their fertility fully intact. Others may have reduced fertility or, in some cases, may need medical assistance to conceive in the future. That is why it is important to ask the oncology team about fertility preservation before treatment starts — not after. We know that conversation is hard when your focus is entirely on getting your child better. We are here to help you have it.

Not all cancer treatments carry the same level of risk to the reproductive system. In general, the treatments most likely to affect fertility are: radiation therapy directed at or near the pelvis, abdomen, spine, or brain (particularly the area near the pituitary gland, which controls hormone signals to the ovaries or testes); and certain chemotherapy agents — particularly a group called alkylating agents, which are often used in treatments for lymphoma, Wilms tumour, sarcomas, and some brain tumours. Other chemotherapy agents carry lower but still real risks. Surgery involving the reproductive organs also carries direct risk. Treatments such as some targeted agents, immunotherapy approaches used in childhood cancers, and lower-dose chemotherapy regimens typically carry a lower fertility risk — but this must be discussed with your child's specific treatment team, who can explain the risk in the context of your child's actual treatment plan.

Fertility preservation is a set of medical steps taken before cancer treatment begins to give a child the best possible chance of having children later in life. The right options depend on whether your child has reached puberty. For teenage boys who have started puberty, sperm banking (freezing a sperm sample) is well-established and straightforward. For teenage girls who have started puberty, egg or embryo freezing may be possible — it requires a short course of hormone injections to collect eggs, and this is done in coordination with a fertility specialist alongside the oncology team. For younger, prepubertal children, sperm and egg freezing are not yet possible because the reproductive cells are not mature. In these cases, ovarian tissue or testicular tissue preservation may be discussed — these are more specialised procedures, and the oncology team will explain what is and is not available at your centre. Not every family will have time before treatment starts, but even a brief conversation with the team is worthwhile.

No — it is never too late to ask. If your child has completed cancer treatment, a fertility assessment can still be done when they are old enough. For boys, a semen analysis in late adolescence or early adulthood can give a clear picture of their fertility status. For girls, blood tests to measure hormone levels (including AMH — anti-Müllerian hormone — which reflects the size of the ovarian egg reserve) can provide useful early information, though hormone levels alone do not tell the full story and fertility specialists can give more complete guidance. Many survivors who do not conceive naturally within a reasonable time can be helped by fertility treatments. Importantly, finding out early — even years before your child plans to start a family — gives more options and more time. Ask the oncology team for a referral to a fertility specialist as part of your child's long-term follow-up care.

Puberty and fertility, while related, are not the same thing. Some children who experience reduced fertility after cancer treatment still go through normal or near-normal puberty, because the cells responsible for hormone production (which drive puberty) and the cells responsible for making eggs or sperm are different. For example, a child can have the hormonal changes of puberty — growth, development of secondary characteristics — while still having a reduced egg or sperm reserve. However, some treatments, particularly higher doses of radiation to the brain or to the gonads themselves, can also affect hormone production and delay or alter puberty. The oncology team will monitor your child's growth and hormonal development during and after treatment. If there are concerns, they will refer your child to a paediatric endocrinologist. Do not hesitate to raise any concerns you notice at home — changes in growth, delayed puberty signs, or anything else that worries you — at your child's follow-up appointments.

Research in large groups of childhood cancer survivors has been reassuring: children born to survivors of childhood cancer — both through natural conception and through fertility treatments — are not at significantly higher risk of cancer compared with children in the general population, except in cases where the parent's cancer was caused by a known inherited genetic condition (such as retinoblastoma, certain cases of Wilms tumour, or Li-Fraumeni syndrome). If your child's cancer was linked to a hereditary condition, genetic counselling is strongly recommended before they start their own family, so that the implications for their future children can be understood. For the vast majority of childhood cancer types that are not hereditary, survivors can be reassured that their children are not at elevated risk from the cancer treatment alone. Your oncology team will tell you clearly if a hereditary factor was identified in your child's case.