This report examines the Family Cognitive Profile Study which provided for the collection and analysis of data regarding the IQ gains of children enrolled in the Mother Child Home Program (MCHP). The existence of siblings among the subjects of the MCHP was noted by the Verbal Interaction Project (VIP), the research organization responsible for MCHP, as a potential source of difficulty in evaluating the program's effectiveness. Since MCHP reaches the child through the intervention of the mother, it was expected that some dependency existed between the IQ gains of siblings. Four "mother exposure" hypotheses, based on the premise that continued exposure to the program changes the mother's behavior toward her children, were formulated to guide the research. Statistical procedures used in the study were also evaluated. The data was drawn from the IQ scores of more than 300 children who were enrolled for at least one year in MCHP. The investigation of the "mother exposure" hypotheses was hampered by methodological obstacles, and only one of the four hypotheses was confirmed. Appendixes compose approximately one-third of the document. (SDH)