1. People want to have a boy child and they never hesitate to abort the female foetus. It leads to decline in sex ratio.
2. Sex ratio declines with increase in female foeticide.
3. Sex ratio declines with the custom of killing new born girls i.e. female infanticide.
4. Emigration of males from one place to another also leads to decline in sex ratio.
5. In traditional societies birth of girl is considered as a curse because of which boys are preferred over girls. It also leads to decline in sex ratio.
