Case reports suggest a familial element in the etiology of childhood brain tumors, but no systematic family studies have been conducted. This genetic epidemiologic family study proposes to collect current health histories on a cohort of 225 childhood brain tumor patients and their family members. We will determine age-specific risks of cancer of all sites and of specific sites in first degree relatives. Segregation analysis will be applied to the brain tumor pedigrees extended according to a sequential sampling rule to include selected second degree relatives under a generalized mixed model to determine a) the extent to which cancer aggregates among proband relatives: b) the frequency of potentially hereditary syndromes in childhood brain tumor patients; c) parameter estimates for the model(s) which characterize the familial contribution of cancer in families with an aggregation of cancer. Findings of this study may be used to define risks to enable genetic counseling and to identify specific kindreds in which specific cancer-predisposing genes may be segregating for future genetic linkage studies.