>>13377765>all genetic modification you do would be undone by sexual selection.I don't think so.
The reason that men and women are different heights is because of how the Y chromosome tends to modulate growth hormone. Y chromosome tends to makes men taller -> people grow up in an environment where men are usually taller than women -> most people develop that preference, and select for it, which keeps the distribution. Women and men are not somehow "genetically predisposed" to desiring male taller dimorphism. They are socialized into this dynamic because it's what they see during development. This is already known because of the massive variation of the preference between as well as within societies. In a society where it's normal for the women to be large and men small, they would develop that preference because that's what they're used to.
Most likely what actually happened, is back when males fought in hand to hand combat, larger males had a slight edge, which made them more likely to have children, which went on to make our species (really a pre-human ancestor species) to develop male larger dimorphism. It was not due to female sexual selection it was due to male on male competition. That's not the relevant selection mechanic anymore.
If we were to modify the Y-chromosome and the Germline of humanity such that the males in our species become very small and athletic and have dense bones, and the females in our species blow up to become giant and thick mommies, then it would take literally tens of thousands of generations of sexual selection against that trait in order to change the y chromosome enough to revert back to male larger dimorphism. This isn't going to happen, because the women wouldn't be selecting against it, and also because the males and females who are properly dimorphic with female-larger dimorphism will go on to out-compete the other societies. They will spread faster, dominate resources more effectively, etc.
