I think it's more likely that the imbalance between the sexes will correct itself through any of the myriad feedback mechanisms before it has a significant effect on Chinese evolution.
For example, parental preference could shift back to girls (or at least even out) since couples will probably be expected to support all four parents in their old age, and eligible bachelorettes will become a valuable commodity. Having a boy becomes an evolutionary gamble: a daughter will surely bring grandchildren but a son may die childless.
For example, parental preference could shift back to girls (or at least even out) since couples will probably be expected to support all four parents in their old age, and eligible bachelorettes will become a valuable commodity. Having a boy becomes an evolutionary gamble: a daughter will surely bring grandchildren but a son may die childless.