That's a very good point, and I have seriously pondered the "What if people could choose the gender/sexuality/handedness etc of their children" problem before yet managed to totally elide it in my post. Hmm. I think what I meant (but didn't say) was that I was restricting my argument to unambiguously positive changes to DNA since even when you do that the argument he gives is bogus. But (a)I didn't say that and (b) There ARE no unambiguously positive changes to DNA (and my language/framing makes it all seem much more unambiguous than it is).

I think my particular disability makes it harder for me to understand this sort of thing: it's a horrible inconvenience which I was happy without for the first 20ish years of my life and would get rid of in a second. Same with my one notable congenital fault eg bad eyesight.

But I imagine being "fixed" to no longer be short, or pale (very maladaptive in Australia!) or female and...yeah. HMM.