What are the factors that affect the sex ratio structure of the population?

There are three main factors that affect the change of population gender structure:

(1) Biological factors. The concentrated expression is the influence on the gender difference of newborn babies and the mortality rate of the population. Male embryos are generally more than female embryos, and women's life expectancy is generally higher than that of men, which makes the sex ratio of the population born in the same year tend to be balanced when they reach marriageable age. With the increase of age, there will be more elderly women than men.

(2) demographic factors. On the one hand, it shows that the change of natural population growth rate affects the sex ratio of the total population, and the high natural population growth rate has a great influence on the sex ratio of the population, and the age composition of the population is light, and the proportion of minors in the total population is large, which will increase the sex ratio of the total population; On the other hand, the change of age and parity of women of childbearing age affects the sex ratio of babies born. The older a woman is, the more births she has, and the lower the sex ratio of her baby.

(3) Social factors. Such as war, immigration, social system and economic layout, population and fertility policy, the development and application of medical technology, and changes in ideology, lead to changes in the sex ratio of the population.