Well, this is all very hypothetical stuff. There might be no downsides at all! Hell, if I could safely make my future children 6 inches taller and 20 IQ points smarter, I'd do it.

But many people have imagined dystopian consequences - creation of a lifelong underclass; negative side-effects that take decades to manifest; having big corporations and government gatekeeping conception; monoculture and loss of genetic diversity; what would become of us pre-editing humans; impact of state control of genetically-predicated personality traits; and so on.

The movie GATTACA comes to mind which, while fictional raises some interesting ethical questions.

I watched that movie and wished that I could have been the beneficiary of such editing. Once it's possible it seems obvious to want to do it. What's the problem?

I don’t have a problem with it, but certain worldviews would driving motivators in the world would be very upset about gene editing. Like imagine if in 50 years billionaires are biologically immortal. That’d be quite something.

What about the countries, ethnic groups and religions that can't afford to edit the genes of their children.

Is their destiny to be out-competed by those groups with the best gene editing technology?

What if a particular highly effective gene editing technique is perfected and patented in country A and they refuse a license to country B because they are rivals?

What if in country Z only ethnic group X is allowed to receive the treatment?

What do you mean by out-competed? For humans, reproduction has very little to do with the traits that people might want to select for. Just about every group that could afford such treatment is already has a low fertility rate.

The Uber-Han has arrived.