Recent critique of maternal-fetal therapy trial ethical guidance has highlighted the need to weigh maternal, fetal and societal interests, respectively, while deprioritizing psychosocial reasons for participation. Psychosocial reasons refer to the psychological and social influences on study participants' decisions, and they are often central to considerations about informed consent. However, psychosocial reasons are described as too indirect, subjective, and vague to incorporate into prenatal clinical and regulatory frameworks. This qualitative study examines the perspectives of 11 individuals (eight couples) enrolled in one of two maternal-fetal therapy phase I clinical trials for rare genetic conditions. Interviews revealed that motivations to participate were primarily psychosocial, including: existential concerns given prior bereavement and/or fear of loss; temporal control through taking action as opposed to feeling passive; hope and optimism; and intergenerational and social motivations given one's family experience with disease and desire for social connections. Psychosocial reasons for participating ought to be given more consideration in ethical frameworks for maternal-fetal therapy phase I clinical trials, as well as in the approach to informed consent. It is important for clinical research teams to be especially conscientious to ensure appreciation for participants' reasons for participating that extend beyond typical frameworks of clinical risk/benefit, and to support participants who might harbor optimistic expectations of medical procedures as they transition to postnatal realities.