Although announcement of the risks related to treatment has become a general rule in the healthcare relationship, doctors, nurses and parents of severely ill children tend to feel uncomfortable in relation to this mandatory information. The work conducted by the AP-HP Espace éthique working party in collaboration with parents, healthcare personnel and a philosopher demonstrates the need to announce these risks, even beyond the legal framework, while bearing in mind the difficulties and hazards inherent to changes in legislation and by observing the philosophical values that subtend this legislation. Faced with the broad range of diverse and complex risks, the working party proposes a classification of risks and hierarchisation of the difficulties encountered by the doctor during this announcement, which is difficult to make, and difficult to hear, as intimately related to the child's quality of life. The very concept of the probability of a risk raises concepts that are difficult to accept: chance, randomness, and uncertainty. Informing the patient involves hearing as much as talking, listening as much as explaining and requires availability, time, space and an ability to listen to the patient. This article proposes several good practice guidelines designed to consolidate the therapeutic alliance by sharing the uncertainty of the risk and allowing the various partners to remain actors. Nonconfiscation of knowledge by doctors does not lead to a loss or transfer of their responsibility, but allows decisions to be taken in the context of the alliance, while taking the risks into account.