Habits like smoking drinking. Baird 2000. Danish study.
Age. 15 to 49. Menarcge to menpause.
Frequency of intercourse
Sterility of husband.
Socio economic status. Caste and religion. Lower caste women more fertility. Bihar 3 Kerala 1.7. Muslims larger than Hindus. correlation not causation.
Status of women. Urban educated women graduates have low illiterate and primary educated women have higher fertility. Remind me not have control
Male preference create increase fertility till male child is born. Sex ratio 930 India.
Ethnicity. African Americans have high fertility than whites.
Age of marriage. Early marriage increases fertility.
Easterlin argues that aspirations of parents determines fertility rate not income. High expectations mean less children. Good living aspiration means less children and even no children. Rising cost of children reduces fertility.
State might interfere like China had one child policy.