No, I know exactly what you mean and from a physical standpoint it makes perfect sense, although, having said that, the chance of someone like Steven Hawking (for example) finding a successful mate (who doesn't just want to beat him ) and successfully reproducing with them must be pretty low compared to any able bodied person. In that case the chances are that such 'defects' may well not be passed on to new generations anyway. I disagree. Evolution is the natural progression of our species and that doesn't have to be driven by threat in my mind. We don't have to have sabre toothed tigers chasing us for nature to push us forward in some way or other. People are getting taller. You just have to look at houses a couple of hundred years ago to see that. I'm pretty sure that with that comes the natural need for feet to get bigger to aid balance. Now I'm pretty sure we haven't needed to run away from tigers too recently and I don't think we need to be taller to reach higher leaves like giraffe's so that has to be down to gene mutation and evolution of sorts. Anyway, where are the religious folks to tell us that God created us in his image and evolution's one big lie?...