Mutants - the genetically altered, the victim of environmental contamination, the subject of failed medical experimentation, or the natural evolution of the species?
You'll do kindly to remember that each mutant is unique in their abilities. You may not always know what sort of benefit or hindrance they might have and many will go to great lengths to hide their true mutations.
Some are trying to perfect specific mutations to sell to the scientific world. Others are attempting to create a super power of soldiers, or even develop the perfect employee best suited for a job. There are many other reasons, known and unknown and are only limited by the imagination of this advanced intelligence of people.
Mutants may be considered a lesser species to some who prefer the pure blooded of their kind and to others a miracle of time and something to aspire to become.