  A better objection to the Unnaturalness Argument challenges the alleged link between unnaturalness and wrongfulness. Indeed, if crossing species boundaries is sufficient for unnaturalness, and if unnaturalness is sufficient for wrongfulness, then the creation of mules and all other cross-species hybrids, even hybrid lilies, would be wrong. On those definitions of “unnatural” that make human intervention sufficient for unnaturalness, the view that unnaturalness is sufficient for wrongfulness would entail the even more outlandish conclusion that everything humans do is wrong. If the Unnaturalness Argument is to be at all plausible, it must avoid such implications.