Mutations from radiation alter human genetics. We see the more obvious mutations. The others have no reason to reveal themselves. Why go to the doctor if you feel fine? These genetic mutants remain unknown living quietly amongst us.
A large portion of our brain is generally not used. It lies dormant for now, not having evolved into its intended purpose. But for some of the mutants that portion of the brain is fully active. Perhaps this began with radiation in the atmosphere. Perhaps some isolated mutations just naturally began to happen well before the nuclear era.
Like Clark Kent, the Superman usually moves amongst us incognito. Forget the vulgarization about “faster than a speeding bullet” and “able to bend steel with his bare hands.” Those are primitive conceptions of the Superman. In mathematics the Superman may be “more powerful than a locomotive” but physically this need not be so.
Two American scientists, C. Brooke Worth and Robert K. Enders, around 1955 wrote a book, The Nature of Living Things. Somehow the gene groups had been disturbed, they believed. Somehow a new version of humanity was appearing which had intellectual powers far beyond those of mortal men. 
In 2005, Pravda reported about a “new human race of indigo children” which had begun to appear on Earth. A young child easily tells her father how to repair his old tractor. “I do not know how she does it but she is always in the know what is wrong with the machine,” says he. The year 2012 has special significance for the indigo children. “The earth dwellers will be given the opportunity to live in a 4-D world. But the offer applies only to those whose mind has expanded to an essentially new level – the indigo children.” 
An unusual baby boy, nicknamed Boriska, was born in the town of Volzhsky, the Volgograd region of Russia. The parents gave the baby a meccano (a model construction system), and the boy started making geometrically correct figures from it, combining different parts with precision. “I had a very weird feeling that we were like aliens to him, with whom he was trying to establish a contact with,” the boy’s mother said. 
A parapsychologist, Nancy Ann Tappe, developed the concept of indigo children in the 1970s, after she began noticing that many children were being born with “indigo auras”. The idea was later popularized by the 1998 book The Indigo Children: The New Kids Have Arrived, written by husband and wife self-help lecturers Lee Carroll and Jan Tober. Skeptics scoff at this indigo children idea, some saying it is really just “Attention-Deficit Hyperactivity Disorder (ADHD).”  But what if the government greatly fears these indigo children and is suppressing them with pharmaceuticals?
Nancy Ann Tappe began noticing these indigo children in the mid-1960s, but that doesn’t mean it was then they originated. Louis Pauwels & Jacques Bergier were already theorizing on the possibility of mutant Supermen and Superwomen before 1960, and the idea of humanity’s nascent potential occurred before then. In a short story, Le Horla, Guy de Maupassant (1850 – 1893) foresaw beings who played with the human soul like children playing with fire. “HE has come, the being who was an object of fear to primitive races…” 
“If the mutant exists it is likely to have a physical resemblance to a human being, but to be different in all other respects, owing to the fact that it controls its intelligence and uses it unceasingly.” 
It may have been science fiction author Philip K. Dick who compared the camouflaged praying mantis to the idea of other creatures also camouflaged and living in our midst. One such of these camouflaged beings seems to have shown itself to Adolph Hitler. The Nazi Fuehrer once told Hermann Rauschning, the Governor of Danzig, “The new man is living amongst us now! He is here!” Hitler further confided to Rauschning, “I will tell you a secret. I have seen the new man. He is intrepid and cruel. I was afraid of him.” (Background: Hitler Meets The Superman, Ersjdamoo’s Blog, December 3, 2014.)
Science fiction author A. E. van Vogt imagined “Slans”, evolved humans having the ability to read minds and who are super-intelligent. His novel, Slan (also known as In Pursuit of the Slans), was originally serialized in the magazine Astounding Science Fiction (September – December 1940). It was subsequently published in hardcover in 1946 by Arkham House.  These superior beings, the Slans, are hunted down instead of being dosed with pharmaceuticals as in the case of the indigo children.
The silent zones of cerebral matter, the unused portion of our brain, has mutated into activity with some humans. These may be the leading edge of where all humanity is eventually going. The perfect mutant is perfectly camouflaged in order to avoid enforced pharmaceutical repression. Just as we do not see the hands of a clock going round, so too we do not see humanity in general slowly flowing into a more evolved phase.  But although camouflaged, the Superman is already amongst us.
——- Sources ——-
 The Morning of the Magicians, by Louis Pauwels & Jacques Bergier. (Originally published 1960, in France.) Rochester, VT: Destiny Books, 2009.
 “New human race of indigo children appears on Earth”, Pravda, December 8, 2005. http://english.pravda.ru/science/tech/08-12-2005/9357-indigo-0/
 “Boriska, indigo boy from Mars, predicts mammoth catastrophes in 2009”, Pravda, October 29, 2005. http://english.pravda.ru/society/anomal/29-10-2005/9151-boriska-0/
 “Indigo children”, Wikipedia, December 6, 2014.
 “Slan”, Wikipedia, December 6, 2014. http://en.wikipedia.org/wiki/Slan