Originally Posted by Bostonian
I'm not sure why directly selecting for valued traits is worse than indirectly doing so though the choice of a mate.

To mods: I don't know if Bostonian's comment or my reply are appropriate for the forum, as they delve into issues of conscience. Please feel free to delete if you see fit.

Because it is dehumanizing and commoditizes human life. It involves children being treated as consumable products valued only for the benefit they confer to a third party, rather than respecting their innate value as humans. There is also the issue of the techniques requiring the deliberate destruction of multiple embryos for the creation of one "designer" embryo, which itself is a life-ending act.

Mate selection is a method of choosing someone who is compatible with you on multiple dimensions: cognitive, moral, cultural, genetic, etc. It has nothing to do with the genotype of individual children, but with determining the much larger contributing parental genomes. There is no deliberate loss of embryo life in this route.

What is to give light must endure burning.