Armstrong did not test positive in '99.
Cindy, comparing the TDF to marathons is a flawed analogy. Numerous runners have won marathons more than once - agreed, not seven in a row, though.
But consider: one can win the Tour w/out ever winning an individual stage of the race. Armstrong's best performance year was one where he one five of the 22(?) stages.
The times and "bonuses" are compiled throughout the race and the way it is measured is not always the exact difference between the 1st place finish and the last.
His lung capacity and VO2 Max are among the highest in the sport. Combine that with his heart rates - mid 30s at rest and 200 max and size and he is about perfect for cycling.
I'm not saying the sport is clean - but he's tested more than the others; so until he is "caught" I give him the benefit of the doubt.