Sin is a religious fiction. It might even be a specifically Christian concept. People still get sick, grow old, and die because it's natural to do so.
Really? Then why hasn't science explained that? Why hasn't science been able to stop aging and dying? Our bodies are made to last forever, our brains have the capacity to hold countless information...scientists don't understand the aging process or why it happens...why?
And no, it is not natural...we all have the desire to live because we were created that way...