La realidad del embrión humano en los primeros quince días de vida

Abstract

The early embryo is not a simple homogenous, undifferentiated tissue. The zygote (or unicellular phase of the individual) constitutes itself from the very material inherited from its progenitors as a cell with some polarized organization and certain peculiar properties distinguishing it from any other cell: it contains the map of the first cellular divisions and organizes itself into a vital unity in both its spatial structures and own functions. Rather than merely a cell, it is indeed an organism in its simplest initial phase. The “pre-embryo” concept –as applied to the pre-implanting embryos– as undergoing a development stage at which the condition of individual within its species has not been reached –due to the likelihood of giving origin to monozygotic twins as a result from division– lacks biological grounds. An embryo cannot split into two halves because it is asymmetric; moreover, even since the two-cell state, the diverse cells composing it differ from different from each other. The status of any preimplanted embryo (either naturally generated or created in vitro) is in both cases the same: the quality of being an individual belonging in the human species. Though the in-vitro condition drastically impairs the embryo’s capability to develop properly in a harmonized symbiosis process with the mother, this does not mean lesser humanity but the fact that a human being has been generated and placed in a certain situation where the ability to persist in living is limited.