Theoretically, superhuman abilities are possible. At least, some of them are. Superhuman strength, speed, durability, endurance, and senses are all possible to some degree. A manipulation of electricity and electromagnetism in the veign of Electro and Magneto is also, theoretically, plausible. There have been reported cases of people who's bodies generate massive amounts of electricity, although limited control if any exists at all, which in of itself is quite rare. Psychic abilities, such as telepathy and telekenisis, while still under much debate, have yet to be disproven due to a lack of evidence that disproves them just as much of a lack of evidence that proves them. This is all because of the limitations of testing claims of these abilities based on current technology. Of course, the likelyhood of such abilities is small, based on either scenario. The first is that, due to some sort of genetic mutation at birth, you possess these abilities. While this is possible, it's highly unlikely. The number of genetic mutations in the world is small, and the number of beneficial ones would be moreso. The other scenario is that these abilities are artificially gained through gene therapy, chemical injections, surgury, bionic enhancements, and other such methods. This is unlikely due simply to the fact that it would be quite expensive, requiring the resources of a highly succesful conglomorate or a government institution. Neither such organizations would atempt it due to the vast cost and limited profit.