First - amusingly enough in some ways - is that those now rare females are suddenly going to have real pull, much to the chagrin of the culture.

Dowry? It's going to go to bride price and that price is going to be high. Not only that but the women in question, once old enough, are going to start calling shots for themselves and because they are a rare commodity they're going to find themselves with an unusual amount of power for their culture. They, and their families, will not have to 'settle' for some poor match just to get rid of the unwanted girl. Suddenly they will have market power able to wed even 'undesireable' girls as any girl is better than no girl. Those girls are going to go into wealthier families and are going to have more say in the home, particularly in countries where divorce is allowed. Treat them nice or they won't stay.

The other factor is that this problem is going to fix itself on another level. With a new generation with far too many boys, there will be no partners, hence no children for those families. Bloodlines and families will die out and the population will take a sudden plunge, which will probably also do some pretty strange things to the economy.

Wise families will realize the market power that having a daughter is going to bring in 20 years and buck the trend. Foolish ones, well good luck to them, they're going to have issues adapting.