How much a person conforms to another person's memory report can depend on the power and credibility of this person, even if these factors are manipulated by the experimenter. The aim of the current study was to establish whether memory conformity is also affected by power in pairs involving natural power differentials, in this case siblings. Pairs of adult siblings were shown 50 photographs of faces and then given a recognition test where one partner had to answer before the other. The findings showed that what one sibling reported affected what the other one reported. Contrary to our expectations, however, there was no significant difference in conformity between the younger and the older sibling. The implications of these findings are discussed.