No - having a purebreed does not mean it will be free of health problems. Good breeders get tests done to make sure some problems won't be present, but that's something I've heard a lot about too - 'purebred' dogs getting loads of hip and back problems, because of the extensive inbreeding breeders insist on doing to amplify the 'good' traits (usually something stupid like correct ear set or tail length - ridiculous). I have one purebred papered (14-15 months) and one purebred non-papered (I don't want to hear about 'if she's not papered, she's not purebred' - we thrashed that out in another thread), and I've had no problems with either of them (yet), with the latter going on 4 years old. I'm waiting to see with Rebel. Really it's just the luck of the draw - dogs have a massive, MASSIVE amount of genes, just like any other animal, and any one of them could go bad, whether they've been bred to "perfection" or not.