Discrepancies exist between the care of unrelated donors (UDs) and related donors (RDs), particularly regarding medical suitability criteria, consenting procedures and donor follow-up. Changes to the most recent JACIE standards have addressed these issues. We studied 208 RDs who underwent PBSC or BM donation in a single centre during 2004-2013 to determine the impact of regulatory changes on donor care, and assessed the safety and efficacy of stem cell donation in donors not meeting UD medical suitability criteria. We observed significant improvements in donor consenting procedures (P=0.003) and donor follow-up (P=0.007) after stipulations in these areas were introduced. We saw a higher incidence of serious adverse events (SAEs) in RDs not meeting UD suitability criteria (P=0.018), and a higher incidence of SAEs in donors ⩾60 years (P=0.020). Haematopoietic progenitor cell donation is less safe in RDs who do not meet UD criteria for medical suitability. Although changes to JACIE standards have improved practice, development of specific medical suitability for RDs and guidelines around 'grey areas' where risks to a donor are unclear or theoretical, will be important in improving RD safety and standardising practice.