I’ve thought about this question from time to time. It seems to me that it would not be a sin to discover a way to stop aging. I am skeptical that this would happen, but if it did there would be nothing intrinsically wrong with taking advantage of it, in my opinion.
However, in the unlikely case that such a “cure” for aging was found, there would be a lot of hard questions. Would this treatment be available to everyone? If it was only available to some, should Christians try to be among the favored few? What about overpopulation? What would be the implications for questions of contraception and abortion?
Furthermore, one can legitimately question whether Christians ought to be part of the push to find such a cure. Should a Christian scientist work on such a cure? Should Christian politicians vote for funding for such research? What if finding a cure for aging involved using means that were morally questionable (the destruction of human embryos, for instance)?
What is clear is that for Christians immortality in this body and this present life is not the goal. Our goal is to share Christ’s Resurrection. If a morally legitimate way were found to live for hundreds or thousands of years, I see no reason why one should turn this down, any more than one would turn down treatment to prolong one’s life to seventy or eighty or a hundred years. (For instance, I am on medication to prevent my blood from clotting–I have a biochemical deficiency which leads my blood to clot and would probably have killed me more than eight years ago if not for modern medicine. I’m very grateful for these past eight years of life and any further years that God may grant me using modern medicine and other created means. If God chose to give me a thousand years of life, that would be great–I’d get to read more books, for one thing!) But we would have to bear in mind that such an extended life span is not our right, is not a high priority, and is not in fact immortality. (We would still be subject to death, just not to an inevitable death at somewhere around 75-100, give or take a few years, as we are at present.)
Edwin