It is not always clear about what is meant by the term ‘cloning’. In fact, we can mean different things by ‘cloning’:
1) cloning per se, or the production of individuals identical with an original through asexual reproduction, which is common in the plant kingdom and which in principle produces individuals with the same genetic endowment, but not necessarily, since some genetic mutation can occur during the process.
2) ‘cloning’ by Somatic Cell Nuclear Transfer (SNCT), producing a later-born identical twin with the same nuclear DNA as the donor individual but without the same mitochondrial DNA.
3) ‘cloning’ by embryo splitting, producing genetically identical monozygotic twins, but resulting from the recombination of the genetic endowment of male and female gametes.
Case 1) will not be debated here because cloning per se does not refer to human cloning (at least for the time being). Cloning per se refers to a common practice in horticulture, whereby a parent plant is propagated by cuttings. Cloning in plants is made possible thanks to their ability to undergo somatic embryogenesis, a property not shared with humans.
Cases 2) and 3) on the contrary, is important for the inference of an individual’s identity based on existing data and is pertinent to moral analysis. In fact, in ‘cloning’ by SCNT we have a ‘clone’ whose identity can be inferred a priori (that is, ‘vertically’) based on the genotypical identity of the clonable individual, known previously, while in ‘cloning’ by embryo splitting we have an individual whose genetic identity cannot be inferred (‘vertically’) based on information available a priori, but only determined ‘horizontally’, i.e., analyzing the genotype of another genotypical twin.
If we now consider the argument contrary to cloning, based on the right to an un-manipulated genetic endowment (i.e., non-reprogrammed a priori), as a necessary condition for respect for individual autonomy, we note that the moral controversy can only pertain to‘clones’ obtained by SCNT, since nobody would reasonably think of morally condemning the situation of monozygotic twins.