Based on the principles laid out by Darwin, and nearly perfected in subsequent years, we will seperate into two species. One of tall slender beautiful build. The other a lest wholesome looking troll like thing. It will never grow into a cast system due, in large part, to the rise of liberalism, however it will become a more distinct genetic chasm. One day the will trolls find themselves holding the majority of menial labor globally, and will rise up and start a species war. Eradicating the slender species by virtue of a more neanderthalic muscular build. The war will be horrific. The war will also set humanity back several thousand years, both technologically, genetically, intellectually and societally.
Or we could just figure out how to genetically manipulate our sperm and create the perfect human, both physically and mentally. We would then overpopulate the world until there is a major climate collapse and we all die. Which is more likely. Better go snorkeling off the great barrier reef while you can!