Olympic Drug Testing - Why wont Manny allow it?

I just can't see why Manny wouldn't allow it if he has nothing to hide. I have defended Manny time after time saying he aint on steroids but this is very strange (and I am not implying anything). They wont take much blood from Manny, itl be a simple injection... not as if its a pint or anything (well I assume, correct me if I am wrong), so I can't see the big deal. Plus all of this stuff about it affecting Manny and putting him at a dissadvantage (mentally or physically) is bullshit too IMO cause Floyd will be doing the exact same thing, he will have blood taken too so he would be put at the same "dissadvantage" (if you can call it that). Sorry guys, I try to be fair all the time and unbiased, you all know that. But it just seems really strange that Manny would refuse it. Hopefully it is a rumour like Floyd said or its just somebody else and Manny comes to his senses and we get to see one of if not the biggest fight in history.