Argument: Asexual reproduction is sub-optimal for the human species
Dr. George Johnson. "Should A Clone Have Rights?". On Science. Retrieved July 9th, 2008 - "Asexual reproduction, in which all offspring are genetically identical clones, is common in nature in both plants (dandilions are a common example) and animals (some lizard species have only females), but usually only in extreme or high-risk environments, where survival is uncertain. Nature has not favored asexual reproduction in any mammal because the 20% of variation due to nurture is just not enough protection against an uncertain future if you are going to make a major investment in each offspring. It is thus the very nature of our species that places such value on variation among individuals, and I find that the deepest and most compelling reason to carefully consider the implications of human cloning before proceeding."