Ethical assessments of clinical decisions are typically based on the preferences and interests of the individual patient. However, some clinical interventions, such as genetic testing or organ donation, may involve multiple family members. In these cases, one family member may have the potential to benefit, while another family member is exposed to potential physical or psychological risk. In the research setting, the balancing of benefits and risks between family members may be further complicated by uncertainty about their magnitude and likelihood. In addition, when the individual facing these apparently uncompensated risks is a child, the situation becomes particularly ethically complicated, as we appreciated in a recent case. Investigators at the National Cancer Institute were faced with a decision about whether it would be appropriate to disclose apparently “unwanted” research test results (length of telomeres in leukocyte subsets) to an adolescent about risk of future disease (dyskeratosis congenita), possibly causing psychological harm and an ethical wrong. These issues were not expected at the outset of the family's study participation but rather emerged with new data about the research tests. Disclosure of the research finding was an important consideration in order to avoid using the adolescent as a stem-cell donor for his sister. Disclosure to the adolescent could not be justified by merely considering the immediate interests and preferences of the adolescent. However, an expanded ethical analysis that considers the adolescent's familial context offers a more complete picture of the adolescent's interests and preferences which provides justification for disclosure. Published 2008 Wiley-Liss, Inc.