Background Based on the principle of informed consent, doctors are required to fully inform patients and respect their medical decisions. In China, however, family members usually play a special role in the patient’s informed consent, which creates a unique “doctor-family-patient” model of the physician-patient relationship. Our study targets young doctors to investigate the ethical dilemmas they may encounter in such a model, as well as their attitudes to the family roles in informed consent. Methods A questionnaire was developed including general (...) demographic characteristics, the fulfillment of the obligation to fully inform, who will be informed, and the ethical dilemmas in decision-making. We recruited a total of 421 doctors to complete this questionnaire, of which 368 met the age requirements for this study. Cross tabulation and Pearson’s chi-squared test were used to analyze the differences between types of patients for categorical variables, and a p-value < 0.05 was considered statistically significant. Results Our data shows that only 20 doctors (5.40%) stated “informing the patient alone is sufficient” when it comes to informing patients of their serious conditions. The rest of the participants would ensure that the family was informed. When facing elderly patients with decision-making capacity, the data was statistically different (3.8%; P < 0.001) The primary reason for ensuring that family members be informed differs among the participants. In addition, when family members asked doctors to conceal the patient’s medical condition for the best interests of patients, 270 doctors (73.4%) would agree and cooperate with the family. A similar proportion (79.6%) would do so when it comes to elderly patients. Conclusions (1) Chinese doctors pay extra attention to informing the patient’s family, which may not be in the patient’s best interests. (2) Chinese doctors treat adult (but not elderly) patients and elderly patients differently when it comes to informing family members. (3) When family members request that doctors withhold information from patients “in the best interest of the patient,” the majority choose to comply with the request, although this may cause them distress. (shrink)