Performance-enhancing drugs have generated controversy in professional sports for decades as demand for optimum performance ever rises. A new method of performance enhancement has been identified as a possible future problem, a process known as gene doping. As genetic research advances, it is possible that rogue athletes may use genetic technology to enhance their ability through gene doping, potentially improving their performance significantly. Because of the numerous controversies and ethical problems this kind of enhancement may bring, anti-doping authorities have pre-emptively banned genetic manipulation.