Gene doping involves inserting genes into an athlete's cells that stimulate the production of certain genes which are thought to enhance performance. Here are four of the obvious methods. Myostatin blocking Myostatin is the body's way of regulating and controlling muscle growth. A gene that blocks the production of myostatin would encourage muscles to grow. But while the muscles might bulge, the skeleton and organs do not grow in sync. GROWTH HORMONE THERAPY Inserting genes that produce growth hormones would also help an athlete develop strength and speed. But again, the rest of the body does not grow in tandem. Erythropoietin (EPO) therapy EPO encourages production of red blood cells that carry oxygen around the body. Gene therapy could result in greater quantities being produced, giving an athlete higher stamina. But it thickens the blood and could result in a heart attack. Endorphintherapy Endorphins are naturally produced painkillers that can send an athlete on a high while they are exerting themselves. Therapy to produce extra endorphins could help an athlete ignore pain.