Transhumanism is the belief or theory that the human race can evolve beyond its current physical and mental limitations, especially by means of science and technology, to become "superhumans" of sorts. Science fiction addresses this topic quite often, as evidenced by frustrated cries of "Kahn" (a "successful," but evil eugenics experimental human) in Star Trek, while the X-Men movies portray many "mutants" as higher-evolved humans with special superhuman/superhero skills in a positive light (along with some formidable supervillains). But is there any reason to fear — or perhaps even be encouraged by — advances in humankind?
We've already defined transhumanism above, but let's clarify what the terms evolution, science, and technology indicate in that definition. Evolution can mean change— typically uphill. Is man changing? We see such things as the near eradication of some diseases, certainly, but is he evolving in a molecules-to-maniacal monster (such as Kahn) sort of way? While technology, the application of already-acquired knowledge for practical purposes by men, is improving and prolonging man's quality and length of life, it is not a biological change, nor does it produce one. Science, defined as the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment, produces nothing new biologically. Note that the common denominator is the agent of man, not some mystical "improvement ratio" beyond our affect. Man's ingenuity is the impetus for both science and technology, and it is in his best interest to improve his own status. But man works with what is already there, often merely "stand[ing] on the shoulders of giants" as Jurassic Park's Michael Crichton, via the book's consultant mathematician Dr. Ian Malcolm, put it.