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.