I'd be remiss if I didn't draw your attention to the awesome fact that Perry Robinson has discovered the fountain of youth. As he recently explained:
"The magisterium hasn’t defined that issue one way or another. The’ve held off from saying she died. The reason why they haven’t done so is because death is a product of libido. If Mary died a natural death then she had original sin and original guilt."
So, at least where men are concerned, the secret to immortality is chemical castration.
Of course, that carries certain tradeoffs, so it comes down to one of those "Your libido or your life" type dilemmas.