The effects of son-preference in India have resulted in a trade in brides. When the discussions about the phenomenon in China and India (especially) began, some argued that the scarcity of women would give women more power in mate-selection. I knew that was not the case, because an antique vase doesn't get more power when it becomes scarcer: Its owners get more power, though thieves are also more likely to steal it.
The son preference stands on two legs: The first has to do with patrilocal marriage customs which mean that daughters indeed are a burden. They must be fed and reared and then they are sent off, possibly with expensive dowries. Sons, on the other hand, are viewed as the ones who carry the family name and who take care of the family in general. Who stay.
The second leg is the lack of governmental old-age benefits. Sons are expected to take care of their elderly parents, so a couple with no sons is going to be in trouble. Even though daughters in the West do more of the hands-on care of their elderly parents, that task in India is more likely to be assigned to daughters-in-law. That makes daughters even less desirable, because your daughters will care for some other person in old age, not you.
This problem will not be solved until the valuation of women rises (coughfeminismneededcough):
Just one in five women has her name on her house’s papers and four out of five need permission to visit a doctor, the India Human Development Survey revealed. Just one in five women is in the workforce, making India’s workforce one of the most gender-biased in the world.Note that a woman who can earn money may not need a dowry to get married. A woman who can earn money might have more power in both her birth family and in her husband's family. The unpaid work she does at home is deemed as her natural duty and tends not get her more bargaining power.