The thing that worries me the most about these technologies is when we make changes with them, those changes seem fine in the lab, and then when those changes spread in an ecosystem for long enough, suddenly, problems start popping up due to those changes.

By then, it's far too late to undo those changes. The genetic pollution remains forever.

It is therefore far better to have never done any genetic modification at all, because we simply don't understand how one change interacts with everything else.

Nature has done so much better than we have ~ therefore, because we don't understand nature's decision-making process, and never have, and most probably never will, we should never interfere with tinkering with something extremely and profoundly complicated like DNA.

Selective breeding is superior to humans tinkering with the genome directly.