Parental acceptance-rejection theory (PARTheory) is an evidence-based theory of socialization and lifespan development that attempts to predict and explain major causes, consequences, and other correlates of interpersonal—especially parental—acceptance and rejection within the United States and worldwide (Rohner, 1986, 2004; Rohner and Rohner, 1980). It attempts to answer five classes of questions divided into three subtheories. These are personality subtheory, coping subtheory, and sociocultural systems subtheory. Personality subtheory asks two general questions. First, is it true, as the subtheory postulates, that children everywhere—in different sociocultural systems, racial or ethnic groups, genders, and the like—respond in essentially the same way when they perceive themselves to be accepted or rejected by their parents or other attachment figures? Second, to what degree do the effects of childhood rejection extend into adulthood and old age?