Background: When a potential stem cell donor to a seriously ill child is a healthy sibling below 18 years, Swedish parents have the legal right and obligation to decide on behalf of the donor child. However, there are potentially conflicting loyalties when parents have one severely ill child in need for a cure and one healthy child who will be subjected to medical procedures. This study explored parents' experiences related to their decision on stem cell donation, as well as ethical considerations in the donation process where outcomes are uncertain. Method: Individual interviews were performed with 18 parents of 13 minor donors after successful hematopoietic stem cell transplantations. Interviews were analyzed using inductive Reflexive Thematic Analysis. Results: The parents were living with the threat of losing a child, and in this context, the main theme No conflicting loyalties was found and included four subthemes; Focus on the ill child, Sibling as the preferred donor, Obvious that the healthy child should donate, and Keep on keeping on. Conclusion: When a healthy child is a potential donor to an ill sibling, their parents' main focus is on the cure for the ill child. The lack of obvious conflicting loyalties among parents highlights the need to secure an ethical process for healthy minor donors and the importance of a separate donor advocate for these minor donors.