WHY do Parents prefer Sons over Daughters?

The 2001 census showed that there were only 927 girls for every 1000 boys in India.What do you think are the reasons for parents preferring sons over daughters? 

Mainly following tendencies are behind this, Think..............!

 

Sons are an investment, they take care of the parents in their old ageOnly sons can carry on the family lineage, daughters do not belong in the family once they are married

Daughters are an economic burden, the expenses incurred during their lifetime is too high

Girls are more vulnerable than boys. Their personal safety is too high a risk for parents to take care of