Being natural means being behind. We dope our active kids so they'll do "better" in school. We used to show coffee on TV ads as pleasant tasting and even relaxing--that has been replaced by energy-drink ads touting performance-enhancement as the way to make it through the work day. We all but demand new world records in sports using every "legal" means, but are dismayed when athletes cross an arbitrary line.
So, where do you fall on the blade-runner question in the Olympics? Because it is actually impossible to say "those prosthetics do or don't provide 'extra' performance" what happens when a world record is set by a blade-wearing athlete? What if parents were given the option of enhancing (how about just ensuring it was optimal for its genes?) their fetus' intelligence, physical health? Would you deny your child an equal footing with children who have had that help? If not, what if they could stop/repair birth defects, genetic flaws, would you give that to your child?
Modern medicine is already pushing the limit of what any person's "natural" ability is. A couple generations ago, there were virtually no instances where doctors could perform surgery on an athlete and honestly say "the joint is better than before the injury". That isn't true any more--it is more than theoretically possible to operate on a knee and give the patient a "better" knee than they were born with.
I'm fascinated with how we are and will be dealing with these "post or trans human" issues. I have no respect for those that cheat, but I do wonder how we're going to define fair in the future.