We present a case of parents who had difficulties accepting their child's treatment (HD chemotherapy and stem cell transplantation) and coping with it. The conversation between the paediatrician and the mother revealed that she feared being dispossessed of her maternal role by the nurses, that constraints would interfere with her relationship with her son, that the medical team would make her feel intellectually, culturally and socially inferior, that the conflict the couple was facing would be exacerbated in this setting. Collaboration between the paediatrician, the nursing staff and the psycho-oncologist allowed these conscious and unconscious elements to be understood. Talking, not conflict nor constraints, served to allay their fears, to avoid inappropriate reactions of the medical team, to preserve the therapeutic alliance. The child accepted this trying treatment because he saw that his parents were reassured about its quality and about preserving their sense of identity and their value. Coping difficulties may stem from fear of treatment (too trying physically and psychologically), from its consequences (destabilisation of the family, the individual's social and professional status, his/her sense of identity), from rekindled old problems that were not adequately solved (jealousy, revolt, trauma, bereavement). Dialogue and team work are necessary to solve them.