First things first: I am an atheist. So I don’t have any God-related issues concerning rejuvenation/living forever.
Some people, though, may believe there’s an afterlife waiting for them once they die, or that reversing the ageing process equals playing God. What I think of that kind of belief is not relevant. Suffices it to say I don’t hold it in very high regard.
I don’t think this is a particularly problematic objection. If anyone at all, believer or not, wishes to die at any point, I am in no position to object. It’s their life, not mine, and they can do with it whatever they see fit. If you are afraid of never reaching your god because of quasi-immortality, I think you should be free to die the way you wish, be it by ageing, suicide, or whatever way you prefer. I think it’d be crazy to terminate your life for this reason, but hey, whatever
sinks floats your boat. It’s your choice, and you should be given it. Rejuvenation isn’t about forcing people to never die. It’s about giving them the possibility of living in perfect health for as long as they see fit.
Speaking of the ‘playing God’ problem, I think the real problem is one of definition. What does ‘playing God’ mean? Is it defined anywhere in your holy book? Why is curing ageing ‘playing God’, but curing diseases isn’t? We have already established that curing ageing doesn’t make you immortal. Rejuvenation isn’t about throwing a challenge to your god. It’s about putting an end to people’s suffering, which I understand gods generally appreciate. (When they aren’t in the mood for plagues anyway.) If your god is almighty and all-knowing as you probably think it is, I’m sure it will take your and everyone else’s life whenever it sees fit anyway. I wouldn’t be afraid of its judgement after your death: You supported a cause that prevented people’s suffering, including your own. That’s pretty damn noble. Also, deaths that are perceived as inevitable, even that of a five-year-old kid killed by cancer, are more often than not interpreted as God’s will by religious people. ‘It was his time’, ‘God has called him’, ‘He rejoined with the Father’, and all of that jazz. However, if we happen to be able to save the person’s life, then the interpretation becomes, God decided to save him/her. Now just what makes you sure God doesn’t intend to save billions of lives by having us develop anti-ageing therapies?
Objections to living ‘forever’
Objections to rejuvenation
All answers in short