Somehow I'm foreseeing the gene modification is inevitable (just as much as us turning ourselves into cyborgs) and people may start arguing more that the same technology that is used to cure diseases and anomalies that make lives of some people hard, but knowing the human history it might not be good idea in long run due to all biological and technological dominance becoming even more possible, as mentioned earlier in the thread. It's already fairly easy to break a person or control masses with right resources and skills though.
I admit in my opinion it would be cool to get superhuman everything, but I wouldn't consider it very ethical to meddle with what nature has given to us. After few generations we'd lose our ability to value difference/variety and sense of compassion/love for those who are less privileged and eventually also for ourselves. Sometimes those who were different or less privileged were able to turn it into a strength in long-run and they helped whole humanity go forward. Would we have that anymore?
As for those who choose to reproduce, the child is more likely to become an object than a person if their genes were chosen or hand picked rather than letting the nature to do its work regardless of outcome. What develops of an object (of course both nature and nurture affect this)? What about animals? Would they become mere servants and food, would we value wildlife at all? Could we see beauty and strength in what's natural anymore? Would an individual have a choice and where would the line of individual having a choice over themselves be drawn, so that it'd be fair?
On idealistic level though everyone would have equal opportunity for success even if it didn't ensure outcomes, because physical limitations wouldn't restrict an individual achievement anymore. Everyone could do what they love. There might be virtual immortality, too.
Baby Gaga said:
Even if these technologies take a long time to trickle down to the lower classes, I am still for them. I think it's utterly selfish to condemn future generations of people to illnesses and limitations that aren't their fault, and stop the advancement of an entire species just because I, a member of the underclass, may not get to see any of it.
Regardless of selfish or selfless, we can't probably control it, but gonna agree with you that we shouldn't (harshly?) condemn a generation for things which may not be their fault. The only solution would be destroying all that there is so far, which is ultimately similar to how certain religious people did to most ancient cultures and that was, turn or die. I don't approve of it although it's history and I couldn't affect it, therefore I'm not gonna be mad about it but the legacy of it. We may still collectively be able to affect if we give the legacy of responsibile use of technology instead of legacy of disregard and recklessness.
Still, humanity will destroy itself sooner or later. If it's not war with nuclear weapons or just all human life poisoning and consuming the planet slowly to death (most likely humans will escape the poisoning through advancement instead of taking responsibility of the well-being of our planet), it will probably be technology and gene modification. It's already possible to develop a lethal disease (which resists antibiotics), why not a killer gene? Or a template which determines whether you're a ruler, a soldier or a slave, (imagine ant hive) and in case of rulers, corruption isn't probably gonna be "bred out" of them.