Why did my child get cancer?

Understanding the real risk factors helps parents stop blaming themselves for things that are not causes. Here is what the evidence actually says.

A diagnosis changes everything in an instant. Here is what the first period after diagnosis typically involves, and what you can expect from a specialist paediatric oncology team.

15,000+ patients trust CION Cancer Clinics

Every child’s journey is different. Our specialist paediatric oncology team is here to understand yours, answer every question, and build a plan around your child — not a generic protocol.

• Why did my child get cancer? Did I do something wrong?

  No. This is the most important thing for you to hear: childhood cancer is not caused by anything you did or did not do as a parent. It is not caused by diet, stress during pregnancy, vaccinations, mobile phone use, or any decision you made. In the vast majority of children who develop cancer, the cancer arises from a random genetic mutation that happened in a single cell — often before birth, sometimes early in childhood — that caused that cell to divide without the normal controls. This was not within your power to prevent. Scientists around the world continue to study why these mutations occur. In most cases, no one cause is ever found. Your child's cancer is not your fault.

• What actually causes cancer in children?

  Most childhood cancers are caused by random changes (mutations) in the DNA of a cell that arise during normal cell division. These mutations are not inherited from parents — they happen spontaneously. A small number of children carry an inherited gene variant (such as those linked to retinoblastoma or Li-Fraumeni syndrome) that increases their risk, but this accounts for only a minority of cases. Known environmental risk factors in children are far fewer than in adult cancers: high-dose ionising radiation (such as from previous radiotherapy treatment) is a confirmed risk factor, but everyday exposures like X-rays or phone signals are not. Unlike adult cancers, childhood cancer is not linked to lifestyle, smoking, alcohol, or diet. In most children, the cause remains unknown.

• Could this have been prevented or detected earlier?

  For most childhood cancers, there is no known method of prevention because the mutations that cause them arise randomly. Unlike some adult cancers, there are no proven screening programmes for healthy children that reliably detect cancer before symptoms appear. Some children with a confirmed inherited high-risk gene variant (identified through genetic testing after a family history) may be monitored more closely, but this applies only to a small minority. If you noticed something seemed wrong and acted on it, you did the right thing. The speed of a cancer’s development and the timing of diagnosis are rarely something parents can control. What matters now is getting an accurate diagnosis and the right treatment plan in place.

• Is my child's cancer genetic? Could my other children get it?

  Most childhood cancers are not inherited. The mutations that cause them happened only in your child’s body and cannot be passed on to other children or to future generations. However, a small number of cancers — particularly retinoblastoma, certain kidney tumours, and cancers in children with known genetic syndromes — do have a hereditary component. If the treating team suspects an inherited cause, they will recommend genetic counselling for your family. In that setting, your other children may be offered specific testing or monitoring. Your child’s paediatric oncologist will tell you whether hereditary factors are relevant in your child’s case. You do not need to worry about this for every child with cancer — it is the exception, not the rule.

• Is it normal to feel guilty or angry after my child's diagnosis?

  Completely normal. Almost every parent we speak to describes exactly these feelings — guilt, anger, helplessness, or the relentless question of “why my child?” These feelings are a natural human response to a devastating and unexpected situation. They do not mean you are coping badly or thinking irrationally. The CION team includes psycho-oncology support alongside clinical care, because we know that parents and siblings also carry a heavy emotional weight through this journey. You are not expected to simply be strong. Asking for support for yourself is one of the most important things you can do for your child.

• What should I do now that my child has been diagnosed?

  The most important first step is to get your child evaluated by a specialist paediatric oncology team — a team that works only with children’s cancers and reviews every case at a multidisciplinary tumor board before recommending treatment. This matters because the type, subtype, stage, and molecular profile of the cancer all affect which treatment is right for your child. At CION, every paediatric case is reviewed by a team of medical, surgical, and radiation oncologists together. You are entitled to a 45-minute consultation, a written second opinion, and full transparency on treatment plans and costs. The first consultation is free. You do not need a referral to book.