Organs can now be grown!

[Occhidiangela]

If you do not consider ability to manipulate environment an extension of evolution, then overwhelming success might disagree with you.
Survival is the only definition that matters, and survival is defined the greatest variety to adapt to the broadest of adversity. Once you start purposefully letting people die you could save, you start shrinking the pool. Who knows? Maybe the genes for cancer will be pivotal to our survival in the future. More realistically, there could've been other traits that we'd lose.

So, we might end up cyborgs, but that is still survival. Although at this point, many of us may alread qualify, having been either sewn up like frankensteins with plastics, bones replaced with metals and silicone implanted in esthetically pleasing areas.
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Breeding cows, horses and dogs for particular traits has had some successes, and some drawbacks. Hip displasia in retrievers is one such drawback.

I have read varying comments on how narrowing the gene pool influences resistance to disease. Since microbes evolve and adapt as well, the resistance trait is up against a variable threat. Since our observations have been done within the context of centuries, and the gene pool has been established, via mixing, over millenia, I wonder at how much we actually know, and what we are still guessing at. I'll bet the over on the guesswork.

Occhi