While genetic redundancy and other DNA surveillance mechanisms may lessen this risk, the large number of human genetic syndromes that involve mental retardation or altered neurodevelopment are a cause of concern. But most importantly, animal models for assessing subtle or even not so subtle changes in neuroperformance the kind that could significantly alter a human life but might be hard to detect in the consciousness, emotions or thought of your average lab mouse are not adequate. That s why the recent spate of reports of maldevelopment and mutation in another scientific arena reproductively-cloned animals concern me. If we are detecting changes with our crude observational methods, consider how many more of these animals have subtle alterations that we cannot identify but which could lessen brain functioning when present in humans. While safety-related data protecting our brains, if you wish provide the clearest line of evidence that precludes human reproductive cloning, I do not think the argument should be settled on that point alone.
Every human generation holds the promise of a new species in an evolutionary sense.
For instance, the changes that make adolescents and young adults so typically foreign or challenging to their elders are not genetically mediated but, rather, the result of cumulative historical, social, economic and cultural forces. These influences have changed us more quickly and just as assuredly as DNA mutations or chromosomal variations over the millennia. But for the first time, the next generation will have powerful biotechnological tools that can alter the genome passed on from one human to the next, as well as the overall pace of biologically-mediated human change altogether. Our enterprise may create a new human species by cloning or other genetic manipulations. Unlike the integrated changes that history and culture offer, this new path to change poses profound challenges to human agencies.