The idea of transhumanism implies a rejection of the body, or at least the body's physical limitations. Transhumanists advocate a dramatic enhancement of human capabilities through the integration of technology with human biology.
Previously unthinkable versions of this involve patients opting for more extensive amputations that replace a limb with what Dominic Basulto describes as "a new generation of 'beautiful' prosthetics." Basulto also points to the example of a paralyzed woman who was able to complete the London Marathon with the aid of a bionic suit.
These are tremendous advances, of course, and yet our growing acceptance of such integrations of technology comes with a cost. The more we rely on technology the less use we have for our bodies. We're getting alarmingly fat. You can't blame that all on technology, of course, but as Pamela Haag writes, America's "epidemic" of obesity springs from a newfound hatred of our bodies: "If Michelangelo’s David was the physical expression of a humanist society," she argues, "then obesity is the physical expression of a post-humanist society."
When you no longer use a part of your body, it atrophies. So what happens when the body ceases to be a relevant agent in our most vital human endeavors?
The brain now has primacy in our technologically-driven world, as we become more and more disconnected from manual forms of labor that are better done by machines. So what's to become of us when computing power hits the steepest part of the exponential growth curve?
We evolved from the simplest of organisms that were all body and no brain. Our technological co-evolution is heading (if Ray Kurzweil is correct) toward a kind of organism that is brain, augmented by AI, with a prosthetic body. (The good news, according to Kurzweil, is that we will still have sex. We'll just skip the death part.)