  Conceding that unnaturalness is not sufficient for wrongness, however, opens the proponent of the Unnaturalness Argument to a further challenge, that of providing principled grounds for distinguishing between those cases in which an act is wrong because it is unnatural and those cases in which an act is unnatural but not wrong, and of showing that creating chimeras falls into the former category. If the Unnaturalness Argument is intended as an extrinsic objection, there are several detailed frameworks available for addressing risks to public health, the environment, or the non-human animal research subject. Any extrinsic Unnaturalness Argument is free to apply those frameworks to chimeras, but will be incomplete until it actually does so. If the Unnaturalness Argument is intended as an intrinsic objection, then Paul Thompson’s observation regarding intrinsic objections to the use of recombinant DNA techniques states the problem succinctly: “no one has succeeded in articulating a principled way of stating why the unnaturalness associated with the manipulation of DNA is unethical, while ordinary plant and animal breeding, computers and modern transport are not” (Thompson 2000, 9).