A Possible Consequence of Polygamy
Fourth Checkraise is discussing the consequences of the legalization of polygamy:
On the other hand, one part of me mischievously wants polygamy to become legalized and widespread, since a society that has to effectively stomp down a quarter of its young males simply could not and thus would not be very liberal in most other aspects either, the realities of the zero-sum race undeniable to everyone who wants their children to have a good life.One possible scenario: Parents who have some reason to believe their children won't be likely to get to the top of the heap might opt for only having daughters. (There might be a method of selecting sperm by then; I'd rather not recommend sex-selective abortion.) Since the poor outnumber the rich, there might be more women than men.
Right now, that seems unlikely; sex selection currently favors males. On the other hand, those parents willing to have daughters will be a disproportionate share of successful grandparents. We can expect sex selection to tilt in the other direction.
One way to look at this is that the resources devoted to raising boys and girls will be the same but divided among fewer boys.
The real problem will be signaling. People who aren't that talented but who try signaling talent anyway might insist on having sons.