The risk of developing any type of brain tumor, and specifically a medulloblastoma, turned out to be up in carriers of the minor 606G allele of the CYP1A1 gene (for all types of tumor - p = 0.009, according to the two-sided Fischer test, OR= 1.50, 95% confidence interval 1.11–2.03, for medulloblastoma - p = 0.026, OR = 1.60, 95% confidence interval 1.06–2.41). The gene discussed is CYP1A1; the disease is neoplasm.