
There have been a few posts above that run along the lines of "Anti-aging can't be good because it would lead to increases in population and greater demand on natural resources." or, following a more philosophical line of "Surely death is part of life and we must accept our fate" - the old Four Score and Ten line, as it were.
Now, whilst I don't wholly disagree with those sentiments (especially as regards over population), I'd like to take the opportunity to play devils advocate for a moment (I can almost never say that phrase without a recollecting Homer Simpsons Pinball machine. heh.)
* The ideal population for earth, according to NeoCon philosophy in the US is approximately 600k - Yes, six hundred thousand, less than 1% of current levels. This figure is the 'optimal level for resource sustainability' - well, we're already WAY outside of that!
* The largest populations occur in the least wealthy nations as a rule of thumb, so I doubt that they will benefit from the emergence of a (no doubt) very, very expensive designer drug in the west. We need only to look at how the various AIDS treatments have been handled to see the effect that such a drug would have on the 'emerging world'.
* It was only a century ago that the average life-expectancy of persons living in the western industrialised nations was around HALF of the current expectation, yet we don't complain that people are living too long by those standards. The idea that life is curtailed by some 'moral marker' in the form of 'an appropriate death following a suitable life' is purely a religious construct, and not a biological one. This increase in life-span is no less natural than the idea of a drug found in soil - we've brought it about through our science; understanding diet, surgery, and far less 'natural' drugs, as well as through social evolution. I don't hear anyone saying that these are bad things (well, maybe some religious fundamentalists, but they are barely worth listening to.)
* If resources were correctly managed, and not owned by vast multi-national corporations (who stockpile and waste on incredible scales) then the population of Earth could be easily sustained. It's not that there are insufficient resources, it's that the resources are owned by a tiny fraction of the global populace.
Overall, I think we should welcome anything that enchances the length and/or quality of life for all human-kind, but it should be a cautious welcome until we truly understand the ramifications of the technology in question.