Comment Re: Or maybe (Score 1) 57
And some things can never be proven from tests. Blood transfusions, for example. Initially, you could identify this case under a microscope, as they actually froze the blood. Now, the blood is simply chilled, not frozen. No damage, no change from what naturally appears in one's blood. There's even been a couple of cases of identical twins showing up to a race, with one there only to 'offer support'.
The other fun specter creeping in is gene doping. Increase production of *something* - hemoglobin, ACTN3 (variant skeletal muscle protein, oddly pro-sprinters have one version, pro-marathon/triathletes another), there was even talk of some trying the CF gene therapy to increase lung efficiency. Again, you would see the results of the alteration, but no proof that the alteration was done.
In biathlon, there is a family that keeps winning, due to what is commonly known as the 'double hemoglobin mutation'. Essentially, they overproduce EPO, the same drug that got Lance Armstrong banned and stripped of all his titles. One can look at ratios of X to Y all you want: the reality is that these people have a huge *natural* advantage.