Molecular data, essential for genomics research, can be captured more efficiently in large-scale, population-based biobanks of genetic material rather than by individual studies. Biobanks also offer improved quality and reliability of genetic samples and access through automated sample retrieval. However, it is challenging to adequately inform participants of the broad nature of the research and participation risks and benefits. In addition, recent studies suggest concerns about data sharing and return of research results, or future research topics (eg, stereotypical or potentially stigmatizing traits). We evaluated the interest in participating in a biobank and reasons for nonparticipation.