Stem cell repositories, similar to many areas in human scientific research, must balance the interests of the individuals who donate their time and samples to science with the interests of scientific progress. This article seeks to explore how sustained interaction with stem cell donors can advance key donor interests (autonomy and privacy) while also increasing the scientific utility of stem cell lines. The ability to trace stem cell lines to their respective donors - underpinned by robust informed consent - enables donors to gain access to information regarding research outcomes and the uses of their biological samples, while also supporting basic and clinical research by providing a means for quality and safety controls. Measures to recontact donors and also to enable donors to withdraw from research should be well designed to ensure donors' preferences are respected while mitigating negative consequences resulting from limited data availability or compromised sample quality. To guarantee the integrity of research while respecting donors' autonomy and preferences, stem cell repositories require a prospective approach to informed consent.