Mutating human genes to make "X-men"?

I'm asking this in a hypothetical, ethical issues aside, strictly for a novel sense. Is it possible, using genetic engineering and stem cell research and such to mutate genes and create super human, almost x-men like people? For example, take a person who happens to be genetically stronger than most, is it possible to enhance that strength? I know scientist would first need a complete template of the human genome specifically, but how and could it be possible in the far far far away future?