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.