On a wider scale, certain research activities need to be restricted by legislation because of the recognized risks of the methodologies involved. Numerous advances have been made to overcome infertility using byproducts of in vitro fertilization that expand the options for the infertile couple. Welfare of those who benefit from assisted forms of reproduction must be measured against potential harm. Concern regarding harm applies not only to the potential parent, but also to the offspring and to society in general. Since the experiments leading to the creation of Dolly were successful only after numerous failed attempts, the efforts entailed to achieve a single success are staggering.
Hazards associated with cloning include both physical and psychological risks.
Cloning is also perceived as potentially harmful to society by interfering with normally held family values. The issue that humans require a personal unique identity has been raised, because the exact same genome would exist in the offspring derived from somatic cell nuclear transfer as in the individual providing the nucleus. This duplication may even be separated by a significant age difference. It should be apparent that environment also influences individual development. Even in homozygous twins individual differences occur and possession of the same genome does not necessarily conflict with uniqueness of identity.