The Gender Imbalance Disequilibrium

China’s gender imbalance is now 117 boys for every 100 girls and for second and third children (when allowed) the imbalance can be as high as 151 boys for every 100 girls.  Millions of men, perhaps 15% of the population, may not be able to find wives.

"The world has never before seen the likes of the
bride shortage that will be unfolding in China in the decades ahead," says AEI demographer Nicholas Eberstadt.

The Chinese government has responded by making selective abortion illegal and by giving significant bonuses to parents of girls.  Yet blackmarket ultrasound is available and, according to 60 Minutes, in demand.  Some reports suggest that the gender imbalance is increasing.

Yet from the perspective of evolutionary fitness having a girl in China is now much better than having a boy.  Boys who can’t find mates won’t be giving their parents any grandchildren.  Will it take a generation of parents without grandchildren for evolutionary incentives to kick in?  Why hasn’t this happened already?  How hard is it to figure out that having a boy, especially if you are poor, means the end of your lineage?

Hat tip to Paul Rubin for pointing out this puzzle to me.