Participants whose willingness to volunteer in a research protocol may be unduly influenced by the expectation, whether justified or not, of benefits associated with participation, or of a retaliatory response from senior members of a hierarchy in case of a refusal to participate. Participants may be vulnerable based upon the class of individuals in which they may permanently or temporarily be associated. Additional safeguard are (1) always given to selected classes (prisoners, individuals kept in detention facilities, children, and neonates), (2) sometimes given to selected classes when they are the focus of the research (pregnant women and human fetuses) by federal regulations. The IRB may also require additional safeguards to others groups based upon the details of the proposed research protocol. These may include patients with incurable diseases, individuals with diminished capacity or incapable of giving consent, persons in nursing homes, unemployed or impoverished individuals, patients in emergency situations, ethnic minority groups, homeless persons, nomads, refugees, military, "normal volunteers" etc.