mother-sister syndrome
 n.— «General Miller’s observation matches common wisdom among experienced intelligence officers that women may be effective as interrogators when seen by their subjects as mothers or sisters. Sexual taunting does not, however, comport with what is often referred to as the “mother-sister syndrome.”» —“Red Cross Finds Detainee Abuse in Guantánamo” by Neil A. Lewis in Washington, D.C. New York Times Nov. 30, 2004. (source: Double-Tongued Dictionary)