not can, will mutate Every single replication of your DNA will contain errors as the DNA replication machinery is not perfect. (this is how cancer forms) Sexual reproduction sees to it that random mutations that are passed on are renederd insignificant. The thing is for your lifetime these mutaions are either doing nothing or cells with them are destroyed when it is detected. A clone, then its clone may be OK but after too many times serious genetic problems will occur which can be fatal, or in a very very rare case cause a superhuman (the liklyhood of this is very low I might add, especially as there will be little selective pressure for improved traits, especially with cloning)