Offspring sex ratios among male tobacco smokers in Khartoum, Sudan.

OBJECTIVES To explore any association between paternal tobacco smoking and the offspring secondary sex ratio, as well as the effect of duration and intensity of smoking on gender ratio. METHODS The cross-sectional study was conducted around major public areas within Khartoum, Sudan, between August and September 2008 and involved 458 married Sudanese males with offsprings. The sample consisted of 111 (24.2%) smokers and 347 (75.8%) non-smokers who were evaluated using a questionnaire on their offspring gender. Data on duration and intensity of smoking was also collected from the smokers' group. SPSS 16 was used for statistical purposes. Chi-square test was used to test for significance of associations between variables. Analysis of variance (ANOVA) was used to test for significance between ratios. RESULTS The number of cigarettes smoked in males increases the likelihood of having a male offspring. The gender ratio in non-smokers was 1.11, while it was 1.15 in smokers. CONCLUSION Paternal smoking increases the offspring sex ratio.