The world of Ruquelis has some problems. It is populated by men, women and winged lilim as in this question: How to get the Lilim to breed true?. People on Ruquelis reincarnate according to the mechanism I describe in this question: Is it reasonable that a nation reject reincarnation?.
Ruquelis has some pretty distasteful customs, including the mass removal of girls who do not become lilim by their ninth birthday from the gene pool, by execution, forced sterilization and/or cannibalism, that have been reinforced by reincarnation. Part of these problems have been compounded by a drug, hialutabu, which makes its users experience pain as pleasure, which is administered to the girls or women to be disposed of in order that their next incarnations remember the experience in a positive light.
The worst part of this systemic prejudice against women is that children born on Ruquelis are raised to believe that women have no value as parents, that their only value is for what they can learn before their deaths and reincarnation, and perhaps for the value of their flesh for the meat trade, and that their deaths are both a positive personal experience that will be remembered by their next incarnation and a positive contribution to their society.
These customs arose as a response to the birth ratios of breeding between men and women, and men and lilim: all offspring of women are 1/2 men, 1/2 women, while the offspring of lilim are 1/3 men, 1/3 women and 1/3 lilim, and have a slightly lower birth rate than women due to 1/4 of fertilized ova being non-viable. Going by pure mathematics, this would appear to be a recipe for the extinction of lilim.
I am considering the implications of an outside party genetically altering all lilim so that instead of the birth ratio described above, lilim bear 50% men, 50% lilim children, and half of their fertilized ova are non-viable. This would be done in an attempt to eliminate the Ruquelians' vile and murderous customs.
Is it reasonable to assume that in a Ruquelian society with reincarnation reinforcing tradition, that such a change would result in a drastic crash in the population of women that might result in their extinction, or would the value of women as the only source of new women increase, leading to their being allowed to reproduce in order to provide new woman-children who could be used to continue the Ruquelian traditions?
Further, if the value of women rises as their population falls in the areas with a tradition of cannibalism, is it reasonable to assume that the traditions of killing, sterilizing or cannibalizing them will abate as it becomes too expensive to continue them?