Deferential vulnerability is when a person feels subordinate to another person due to social class, knowledge, or gender. Many people feel this way when they compare themselves to medical doctors due to the physicians having more knowledge and being considered to be of a high social class.
Individuals may also have deferential vulnerability for cultural reasons. In western society, it is more common for individuals to make their own decisions about medical treatments, but in non-western societies, this may not be the case.
Indigenous cultures often have traditional and patriarchal hierarchical systems in which the head of the household, usually the husband, makes all the decisions. This can extend to decisions regarding medical treatment of a child and giving informed consent for such treatment.