Literally posts this in thread about it having already happened.
If you're into post-humanism, authoritarianism, collectivism, etc and don't care about our species, then it makes sense to support and promote this. It will replace the very evolutionary pressures that have built us over the eons and lead to total harmonization. And not only us; other organisms will receive the 'betterment' treatment as defined by whichever individual, group, faction or government deems which traits are better or worse.
In short, this will result in the complete and utter extinction of all species on the planet. They will be replaced by engineered life forms and they will all tend toward centralization/hiving-because whatever the system, power always corrupts, without exception. It makes absolute sense for those who already control the reigns, to engineer people on the basis of economics and subservience.
You will end up with a world that would make the most eugenic Nazis sweat in terror. That is assured the second this technology is proliferated. Forget Gattaca. That had men, women, black people. The real brave new world will be built for optimal efficiency and control. Every NPC will look identical. Gender won't be relevant as sexual reproduction and reproductive rights will have been eliminated. There will be no sex organs, no varying skin colors. It will all be uniform and precise down to the emotional responses tailored for each caste.
The cat ears, furry suits-all that fun stuff will be reserved for the elite.
Now throw in the prospect of runaway self bettering AI, which would assuredly seize the reproductive and engineering reigns of the castes from the bunny eared over-engineered elite, and you have a dystopia that cannot be escaped or even prevented IF this technology starts being utilized regularly by multiple competing groups.
Fun and related:
Geneticists accidentally engineer mice with especially short, long tails- Scientists stumbled upon the genetic pathway that controls tail developmental in mice. The pathway was discovered accidentally by two separate research groups, both investigating genes related to physiological development.