Document Detail

Could a zygote be a human being?
MedLine Citation:
PMID:  19076123     Owner:  NLM     Status:  MEDLINE    
This paper re-examines the question of whether quirks of early human foetal development tell against the view (conceptionism) that we are human beings at conception. A zygote is capable of splitting to give rise to identical twins. Since the zygote cannot be identical with either human being it will become, it cannot already be a human being. Parallel concerns can be raised about chimeras in which two embryos fuse. I argue first that there are just two ways of dealing with cases of fission and fusion and both seem to be available to the conceptionist. One is the Replacement View according to which objects cease to exist when they fission or fuse. The other is the Multiple Occupancy View - both twins may be present already in the zygote and both persist in a chimera. So, is the conceptionist position tenable after all? I argue that it is not. A zygote gives rise not only to a human being but also to a placenta - it cannot already be both a human being and a placenta. Neither approach to fission and fusion can help the conceptionist with this problem. But worse is in store. Both fission and fusion can occur before and after the development of the inner cell mass of the blastocyst - the entity which becomes the embryo proper. The idea that we become human beings with the arrival of the inner cell mass leads to bizarre results however we choose to accommodate fission and fusion.
John Burgess
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Publication Detail:
Type:  Journal Article     Date:  2009-12-05
Journal Detail:
Title:  Bioethics     Volume:  24     ISSN:  1467-8519     ISO Abbreviation:  Bioethics     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-01-18     Completed Date:  2010-04-20     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8704792     Medline TA:  Bioethics     Country:  England    
Other Details:
Languages:  eng     Pagination:  61-70     Citation Subset:  E; IM    
University of Wollongong, Wollongong, New South Wales, Australia.
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MeSH Terms
Beginning of Human Life / ethics*
Embryonic Development

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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