Abstract
Background: Sex ratio or "ratio between males and females" is one of the demography characters of each population. It is important in genetic, health and medical studies to evaluate the situation of the public health of the societies. Sex ratios in each age group refer to the rate of mortality in that group. Comparison the sex ratios of an age group in two different times lead us to the reasons of its probable changes.
Methods: In present work sex ratios among different age groups in Iran in the first and last year of a ten-year-period were determined and compared. Raw information was obtained from official documents of the two general censuses in 1986 and 1996.
Results: Result showed that, in general, there was a decrease in sex ratios of groups 45 to 95 years in the year 1996 in comparison of the same results belong to the year 1986. In both years of general censuses in all three group populations (Urban, Rural and Nomads) the sex ratios gradually increased as well as the age groups. One of the most important results was that among rural and nomad population, the sex ratios have showed decrease, in fertility ages. Also, the sex ratios in young group 0-24 years (except the group 10-14 years) gradually have decreased, which showed the number of males is decreased.
Conclusion: There was a decreasing trend in sex ratio of male to female during the last three years in both urban and rural regions among all age groups.