Is there ever a level playing field?
Many will have become athletes due to a natural advantage. British Olympic gold medal winning rower Matthew Pinsent has a genetic mutation that means he has a greatly increased lung capacity of 8.5 litres, some 2 litres greater than his long time rowing partner Sir Steven Redgrave. Six times Olympic swimming champion Michael Phelps has size 14 feet, which help to propel him through the water. Anyone who grew up at high altitude has blood with greater oxygen carrying capacity than someone born and raised at sea level.
Would it be ethical to deny athletes drugs which would allow them to compete on an equal level with these individuals? After all this is exactly what happens when we allow athletes with asthma to use inhalers, or those with eye-problems to have laser eye surgery.