With increasing frequency, allogeneic hematopoietic cell transplantation involving children is being performed in the research setting. Allogeneic hematopoietic cell transplantation, however, cannot be performed without a hematopoietic stem cell (HSC) donor. This donor is often a sibling of the recipient and may also be a child. In such circumstances, it is unclear whether or how the federal regulations for pediatric research apply to the minor donors. This introductory paper reviews the issues to be considered while evaluating studies that use HSCs obtained from minor donors and identifies areas where further research is needed. In the era of increasing applicability for donor-derived cellular therapies, we provide a suggested framework for determining when minor donors qualify as human research subjects and when their participation can be approved under the federal regulations.