Data from a large, population-based, case-control study were analyzed to assess 
the role of parental smoking in childhood brain tumors. Parents of 361 cases, 
newly diagnosed between January 1, 1977 and December 31, 1981 and ascertained 
from eight Surveillance, Epidemiology, and End Results (SEER) program 
registries, and 1,083 controls had been interviewed. No significant differences 
in risks were found to be associated with maternal or paternal smoking at any 
time (odds ratio (OR) = 0.92 for mothers and 1.06 for fathers), during the year 
of birth of the child (which included both the prenatal and postnatal periods) 
(ORs = 0.84 for < 1 pack/day and 1.0 for > or = 1 pack/day for mothers, and 0.68 
for < 1 pack/day and 1.07 for > or = 1 pack/day for fathers), or 2 years before 
the child was born, i.e., the pre-conception period (ORs = 0.75 for < 1 pack/day 
and 1.01 for > or = 1 pack/day for mothers, and 0.90 for < 1 pack/day and 1.15 
for > or = 1 pack/day for fathers). Mothers were also specifically asked if they 
smoked during the pregnancy, and no association was found compared with never 
smokers (OR = 1.08, 95% confidence interval (CI) 0.80-1.45) or for ever-smokers 
who continued to smoke during pregnancy compared with those who stopped smoking 
during pregnancy (OR = 1.15, 95% CI 0.75-1.78). Finally, no significant increase 
in risk of brain tumors was found for the child's passive exposure to parental 
smoking during the period from birth to diagnosis of the brain tumor in the 
case. The lack of an effect of parental smoking was observed for both the major 
histologic types and locations of brain tumors. These findings and those from 
earlier studies provide no support for the hypothesis that parental cigarette 
smoking influences the risk of brain tumors in children.