h doesn't appear until after birth. Grobstein concludes that full individuality or personhood is not something that is magically deposited into the ovum at the moment of fertilization, but is a gradual process of becoming that is capable of being scientifically tracked and documented.
Grobstein points out that the developmental process is not even committed to the production of a single individual until approximately two weeks after conception, during implantation in the lining of the uterus. Before this, there is only a "pre-embryo" because any one of the cells could, if separated from the others, produce an entire separate individual. Clinical
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