As a heuristic to facilitate future studies and theory development, a social-cognitive-behavioral model of family systems is used to organize and integrate the sparse knowledge about the experience of heterosexual family members in gays' and lesbians' families-of-origin. The impact of learning that a child or sibling is gay or lesbian on the family system and subsystems and the process of adjustment are delineated. Specific suggestions for research questions within family studies and implications for research methods, clinical practice, and family life education are included. AIthough there is a growing literature on children of gay and lesbian parents (Bozett, 1989; Patterson, 1992), other relatives of lesbians and gays-parents, stepparents, siblings, grandparents, cousins, aunts, uncles, and in-laws-are nearly invisible in the scholarly literature on families. In the few empirical studies in which these relatives are even considered, it is usually the gays' perspectives that are considered. For example, Skeen and Robinson (1984, 1985) studied the perceptions of gay fathers' and gay nonfathers' relationships with their own parents, and Murphy (1989) studied lesbian couples' perceptions of their parents' attitudes, but the perspectives of the parents were not addressed. Only two empirical studies included heterosexual family members as research participants: Robinson, Walters, and Skeen (1989) studied AIDSrelated attitudes of parents of gays; Serovich, Skeen, Walters, and Robinson (1993) found that parents' favorable attitude toward homosexuality was a significant predictor of parents' acceptance of their gay or lesbian child's partner. A search of the qualitative and clinical literatures did yield information from the perspectives of parents and siblings. Many issues were identified from the qualitative and clinical literature and from narratives of family members (Bowen, 1994; Crosbie-Burnett, 1994; Murray, 1994). The lack of quantitative studies from the perspective of heterosexual family members is a reflection of their near invisibility, closeted status, and marginalization in the society in general. This article uses social-cognitive-behavioral theory to integrate the sparse knowledge available on the psychosocial aspects of family relations, family dynamics and the family's social context in the larger society, from the perspectives of heterosexual family members of gays' and lesbians' families-of-origin. The purpose is to promote theory development, research, and teaching on this topic, and also to sensitize practitioners to these issues and provide direction for theorybased interventions with individuals and/or families. A SOCIAL-COGNITIVEBEHAVIORAL MODEL OF FAMILIES The social-cognitive-behavioral (SCB) model of families (Crosbie-Burnett & Lewis, 1993) is used to explain the family dynamics of gays' and lesbians' families-of-origin, by organizing information gleaned from studies, clinical observations, and conceptual articles on this topic (see Figure 1). It is our hope that this model will serve as a heuristic and will be tested empirically and continually modified until a thorough understanding of the dynamics of these families is reached. The SCB model of families is based in the behavioral paradigm and is an application of Bandura's model of reciprocal determinism to families. In Bandura's social-cognitive theory (1986), an individual's motivation, thought, and behavior are explained by a model of causation in which the individual's behavior, environmental factors, and intrapersonal factors all operate as interacting determinants of each other. Behavior includes all observable behaviors; environmental factors include the physical and social context(s) in which an individual lives; and intrapersonal factors include genetic make-up, personality characteristics, temperament, intelligence, abilities, emotions, and cognitions (e.g., perceptions, expectations, beliefs, attributions, values, schemata, learning history). …