摘要
The sex ratio at birth of a given population is not fixed, but affected by the fertility level. Without gender preference, the effect of fertility level on SRB is arisen from the change of composition of birthorder-specific children. When taking into account the gender preference, fertility level affects not only the proportion of birth-order-specific children to total births, but the sex ratio of birth-order-specific children. Fertility rate change is the main reason of fluctuations of the SRB in the countries without gender preference. However, the change of fertility level has a little affect on SRB, and the sex selection is the main reason for the abnormal change of SRB in the countries with gender preference.
The sex ratio at birth of a given population is not fixed, but affected by the fertility level. Without gender preference, the effect of fertility level on SRB is arisen from the change of composition of birth- order-specific children. When taking into account the gender preference, fertility level affects not only the proportion of birth-order-specific children to total births,but the sex ratio of birth-order-specific children. Fertility rate change is the main reason of fluctuations of the SRB in the countries without gender preference. However, the change of fertility level has a little affect on SRB, and the sex selection is the main reason for the abnormal change of SRB in the countries with gender preference.
