In the world of today's medicine, we've made stunning advances in stem cell research for curing disease, prosthetics, regrowing whole body parts, cloning animals, and transplanting organs. We're only going to see an exponential increase in the amount of medical breakthroughs in our lifetimes, I would presume, which leads us to the ultimate question: avoiding death altogether!
It may sound like fanciful science fiction, but I would imagine in roughly a century or two from now researchers will have pinpointed all the various reasons for how the complex biological machines that are our bodies break down and age over time, and more importantly how to slow or even stop this process altogether. What would be the impact of such a discovery and advancement in medical knowledge and practice? Wouldn't everyone alive be clambering to avoid death, to seek this medical solution? Especially if it were cheap and not just a luxury of the super rich and elite? Without an ageing population, we would have a more productive workforce, but also without people dying and continuing to mate and have children, the world would quickly become way too overpopulated. Do you think many people would voluntarily become sterilized in exchange for this medical cure?
Of course, people could still die from infectious diseases, murder, warfare, workplace accidents, etc. However, the chance of death would be immensely diminished, considering how the number one causes of death for the human population around the globe are all linked to ageing and dying naturally.
An even better question, I would imagine, is the revolt and chaos that might occur should the rich try to keep such a medical cure at an exorbitant price, so that only they could afford it, while everyone who is poor basically has to die and watch them live with eternal youth. That would certainly be cause for violent rebellion.