Thank you for this very thoughtful take upon this subject @jrhhewett. I must admit that I found the title of this article in light of your recent generous comment to be particularly intriguing.
I also feel that you could have easily enough have turned this into two different complimentary articles - another one centering around state mechanisms of population control (e.g. the one/two child policies).
My own view on experimentation with genetics is that - as with other 'God-scale' things like Artificial Intelligence - is that there is great potential.
Both for good and for ill. Modification can improve resistance to certain ailments just as it can lead to fresh divides concerning the modified versus the unmodified (and that is stated while treading very lightly upon the potential ethical concerns).
Thank you again. Food for thought.