Presents a literature review examining sex differences in parent–child relationships during childhood and adolescence, and testing the hypothesis that both parent sex and child sex contribute so that relationships in the 4 dyads of mother–son, mother–daughter, father–son, and father–daughter are distinct. Research was divided into 3 groups: (1) only 1 dyad was studied; (2) all 4 dyads were studied, but no tests for differences were conducted; and (3) all 4 dyads were studied and tests for differences were carried out. The research was further divided according to the formal aspect of the relationship being investigated. The literature contained many claims and assumptions about the distinctness of relationships in the 4 dyads, but empirical evidence in support of these claims was limited. Only 1 study with significant difference among all 4 dyads was found. Often there were findings of interactions between parent sex and child sex, but the form of this interaction varied from one study to another, and from one measure to another. Variables associated with findings of interactions between parent sex and child sex were examined. When dyadic distinctness was found, it often was for relationship measures of closeness/cohesion and affective reactions. (PsycINFO Database Record (c) 2012 APA, all rights reserved)