Consensus about contents of voluntariness in informed consent is lacking. Core criteria for voluntary consent are needed to ensure voluntariness. This article outlines the multidimensionality of voluntariness and identifies what could reduce voluntariness, especially in first-in-human clinical trials involving cell therapies. In such trials, truly voluntary consent is especially important because: such trials may involve risk of serious harm, while in case of some diseases, eligible patients often have potentially effective therapeutic alternatives; patients considering participation in high-risk first-in-human trials may feel more desperate and some may be dependent on their caregivers, including those in the family; implanted cells cannot be taken out of the patient's body if the patient wants to withdraw.
Keywords: Parkinson's disease; cell therapy; first-in-human clinical trials; informed consent; regenerative medicine; research ethics; voluntariness.