When we compare to Pre-K programs and other current enhancement that can be bought with money, they are no guarantee that the enhancement will go to the next generations, unless the family can keep paying for those things in the future. So the issue is the starting point of the human life.
Today, we still can believe that all human are born "equal"; but the moment a whole set of human beings are enhanced on a genetic level, a lot of our moral values will be changed forever.
No longer we can say that "All human beings are born free and equal in dignity and rights." if that happens, it will upend things like the "Universal Declaration of Human Rights" and many other concepts that today's society relies on to organize itself. Imagine to live in a society where you are genetically "inferior" and there is no way you can "change" or upgrade who you are.