As examples of big money sport, tennis and athletics authorities and players clearly don't want to confront difficult questions like "there almost certainly be a proportion of players who will be tempted to dope and do so". Until the regime is at least as rigorous as cycling, with the same level of testing, there are very good grounds for suspiscious fingers to be pointed. After all, tennis players freely admit to using needles for "re-hydration and recovery" between matches, something which is now banned ubder UCI regs, and a good thing too! It was enough as a rider, even years ago, to have doctors always wanting blood samples for testing, makes you feel like a pin cushion!