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Bioethics. 2010 Feb;24(2):61-70. doi: 10.1111/j.1467-8519.2008.00689.x. Epub 2009 Dec 5.
Could a zygote be a human being?
Burgess J.
Source
University of Wollongong, Wollongong, New SouthWales, Australia. jburgess@uow.edu.au


Abstract
This paper re-examines the question of whether quirks of early human foetal development tell against the view (conceptionism) that we are human beingsat 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 theconceptionist. 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 andboth 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 botha 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 thedevelopment 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 resultshowever we choose to accommodate fission and fusion.

PMID: 19076123 [PubMed - indexed for MEDLINE]


Traducción posible:

Este paper reexamina la interrogante sobre si las peculiaridades deldesarrollo temprano del feto humano distan en contra de la visión que somos seres humanos en la concepción (Concepcionismo). Un cigoto es capaz de dividirse para dar lugar a gemelos idénticos. Ya que el...