Julian Vigo in Forbes:
Transhumanism (also abbreviated as H+) is a philosophical movement which advocates for technology not only enhancing human life, but to take over human life by merging human and machine. The idea is that in one future day, humans will be vastly more intelligent, healthy, and physically powerful. In fact, much of this movement is based upon the notion that death is not an option with a focus to improve the somatic body and make humans immortal.
Certainly, there are those in the movement who espouse the most extreme virtues of transhumanism such as replacing perfectly healthy body parts with artificial limbs. But medical ethicists raise this and other issues as the reason why transhumanism is so dangerous to humans when what is considered acceptable life-enhancement has virtually no checks and balances over who gets a say when we “go too far.” For instance, Kevin Warwick of Coventry University, a cybernetics expert, asked the Guardian, “What is wrong with replacing imperfect bits of your body with artificial parts that will allow you to perform better – or which might allow you to live longer?” while another doctor stated that he would have “no part” in such surgeries. There is, after all, a difference between placing a pacemaker or performing laser eye surgery on the body to prolong human life and lend a greater degree of quality to human life, and that of treating the human body as a tabula rasa upon which to rewrite what is, effectively, the natural course of human life.
More here.