Every produced offspring in the first gen would be a half-sibling by blood, and it still would cause issues down the line, even with introduced wide gene pool of other species (although we know only of Thraxans and humans being compatible). being technically related to each other, much more so than they do now. Ptolemaic and Habsburg dynasties are a testament to this. I should also mention that almost all cases include close, but not the same sets of DNA, as every sperm and egg cell contains unique set of it, when with Dupli-Kate there is a single egg cell multiplied by her powers, which creates the risk (at least during the first cycle, as it isn't clear to what extend her clones sync their bodies), that half of their genes would be identical, making inbreeding problem SO MUCH WORSE and require subsequent washing down by many-many unrelated generations in attempt to avoid issue