Recall-by-genotype (RbG) strategies are bottom-up approaches to conducting targeted follow-up studies or substudies with eligible participants. They use specific genetic information derived from pre-vious genome-wide association studies or whole-genome sequenc-ing enabled by next-generation sequencing. Genetic information may be partially disclosed when certain partici-pants are recalled for RbG studies, and information on the study design and eligibility criteria is provided. These distinguishing pecu-liarities of RbG approaches have ethical, legal, and social/societal implications (ELSI). In this thesis, we present and discuss the results of research on the ELSI aspects of RbG approaches and within the Cooperative Health Research in South Tyrol (CHRIS) studies (RbG1, RbG2) on genetic risk factors of Parkinson's disease (PD). We used various qualitative and quantitative methods, including in-terviews, surveys and focus group discussions (FGD). Thereby, we sought to address the need for qualitative data from diverse stake-holders, including critical voices in the CHRIS research ecosystem, such as participants, researchers, ethics board members, and study assistants, to develop effective recall and communication strategies through a collaborative approach refining the CHRIS RbG policy. The exploration began with a literature review revealing the explicit and implicit ELSI of RbG study designs. It uncovered a consensus on the significant ethical challenges RbG poses while highlighting the diversity in consent models and Return of Research Results (RoRR) policies employed in different research and biobanking con-texts. Then, a secondary analysis of interviews and surveys from a mixed-methods study with CHRIS RbG participants from the RbG pilot study (RbG1) followed. Alongside the second follow-up RbG study (RbG2) study, we then designed a survey, informed by the results of RbG1, to gather further perspectives on their experience of an RbG study, and other fundamental considerations pertinent to en-gagement and communication in RbG studies. Then, to explore the operational and practical aspects of RbG studies, we identified the relevant stakeholders who shape and decide on RbG study designs. Consequently, we designed and conducted FGD to examine stake-holder perspectives on the RbG study design, communication, and disclosure strategies. Further, we collected feedback and views from CHRIS study personnel and coordinators who accompanied the RbG1 and 2 study process. Finally, we conducted a large-scale sur-vey with CHRIS participants to strengthen the conclusions of previ-ous empirical research. This collaborative approach aims to refine the CHRIS RbG policy, develop effective recruitment and commu-nication strategies, and promote transparency. The study's findings underscore the value of personalised engage-ment and sensitive communication through tailored disclosure and communication strategies. Stakeholder views on ELSI in RbG stud-ies reveal diversity, highlighting the need for adaptable approaches aligned with study contexts. Overall, the results suggest that partici-pants are highly interested in receiving information on carrier status on the genetic variations investigated by the RbG study, but views and motivations were heterogeneous. This adds to the complexity of integrating these insights into communication strategies and disclo-sure policies. More research is necessary to investigate the effects of various disclosure strategies, the impact of disclosure on awareness, and how framing affects participants' reception of study-specific information.

What role should trust have in biobank research? Is it a scarce resource to be cultivated, or does its moral significance lie elsewhere? How does it relate to the researcher’s individual responsibility? In this thesis I draw four general conclusions. First, trust is still very much present in at least some biobanking settings, notably in Sweden, but possibly also internationally. Second, a morally relevant conception of trust entails that to be trustworthy, researchers must consider the normative expectations that people have of them, and renegotiate expectations that are mistaken. Third, this conception differs from “public trust” assessed through surveys. The main use of the latter is to legitimate policy, not to identify moral duties. Fourth, in spite of ethics review, guidelines and informed consent procedures, ethical issues will always arise during the course of a research project. Researchers can therefore never avoid their individual moral responsibility. Ensuring that one is adequately trusted is one step towards conducting morally acceptable research. Study I indicates that few Swedes refuse storage of samples in healthcare-associated biobanks and their use in research. Study II suggests that people are somewhat more willing to donate samples than surveys indicate, especially when approached face-to-face by health care personnel. Relationships of trust might thus be important in people’s decision-making. Study III investigates trust as a moral concept. The trustee is often in a unique position to determine what the other’s trust amounts to. When it is mistaken, the trustee has an obligation to counteract it, compensate for it, or renegotiate the expectations that cannot be met. In Study IV, I critique the feasibility of guaranteeing the trustworthiness of the research apparatus through formal measures such as ethics review and guidelines. Not only are there limitations of such measures to consider. They also risk blinding researchers to ethical issues that are not covered by the rules, fostering moral complacency, and alienating researchers to ethics.