The only recent United States adoption studies on alcoholism for which results have been published are those conducted by Cadoret in Iowa. The fact that only one investigator has been able to conduct such studies may reflect the high degree of tenacity required to overcome State privacy regulations restricting access to information about the biological families of adoptees. In his earliest studies, Cadoret studied samples from Lutheran Social Services (LSS) (Cadoret et al. 1985; Cadoret 1994) and Iowa Children and Family Services (CFS) (Cadoret 1994; Cadoret et al. 1987). More recently, he has also studied samples recruited from a series of Catholic Adoption Agencies (CAA) (Cadoret 1994; Cadoret et al. 1995; Cutrona et al. 1994) and from four other adoption agencies (Cadoret 1994).
