Preimplantation Stages of Human Development: The Biological and Moral Status of Early Embryos



There is currently no consensus on when human life begins, and consequently, the biological, moral, and legal status of early human embryos is unclear. Here, the biological facts concerning early human development are examined to establish a scientific view of when human life begins. The evidence clearly indicates that a new human organism (i.e., a human being) is formed at the point of sperm–egg fusion. The events occurring during preimplantation development provide further support for the conclusion that the early embryo is an organism. The status of the zygote as a complete organism is contrasted to that of human pluripotent stem cells that are best understood as parts of an organism. Two common arguments for assigning human rights to developing human beings are outlined and their logical implications are briefly discussed, in light of the scientific facts regarding human development.


Blastocyst Conception Human rights Organism Preimplantation Zygote 


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© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  1. 1.Department of Neurobiology and PediatricsUniversity of Utah School of Medicine Eccles Institute of Human GeneticsSalt Lake CityUSA

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