Periconceptional smoking and male:female ratio of newborns

We have analysed data collected on 1962 women who gave birth at 37 or more weeks of gestation to health infants (excluding those with a low birth weight and twins). In comparison with non-smoking parents, the odds ratio (OR) of being male was lower than unity for offsprings of both smoking parents, but no clear relationship however emerged between the risk of giving birth to a male, and the number of cigarettes smoked per day. © The Author 2005. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved