I have great respect for the inventor and futurist Ray Kurzweil, though I usually think his predictions are very aggressive. In his defense, he is way smarter than I am. From the Sun:

“WE are living through the most exciting period of human history.

Computer technology and our understanding of genes — our body’s software programs — are accelerating at an incredible rate.

I and many other scientists now believe that in around 20 years we will have the means to reprogramme our bodies’ stone-age software so we can halt, then reverse, ageing. Then nano-technology will let us live for ever.

Already, blood cell-sized submarines called nanobots are being tested in animals. These will soon be used to destroy tumours, unblock clots and perform operations without scars.

Ultimately, nanobots will replace blood cells and do their work thousands of times more effectively.

Within 25 years we will be able to do an Olympic sprint for 15 minutes without taking a breath, or go scuba-diving for four hours without oxygen.”