How is this a problem unique to Creationism? There's going to be an original breeding pair regardless.
You mean, at a time when species evolved to develop sexual reproduction, in the case of the evolutionary model?
If yes, it still is not as susceptible to genetic damage as the Adam and Eve model, because sexual reproduction originated in much simpler organisms. In addition to that, a pool of genetic material was already present, for the species to recover from the damaging effects of mutations.
With a species as complex as humans, this route simply isn't possible, if there is only one pair, to begin with.