H, notice, the zygote forms about a week ahead of implantation and a steady growth process is proceeding in the interim. Implantation is a step of development, not of origin. The biology demonstrates that the point of origin of a unique human life is the formation of the zygote; which about half the time is of a different sex from his mother. Accordingly, once the principle is that innocent human life is respected, it is to be protected from outset. There is no non-arbitrary further point that is properly the beginning. That is the relevance and reason for the reference. KF
Reference: Fertilisation and Implantation
Known facts about biology. Reasonably good diagram.
H, notice, the zygote forms about a week ahead of implantation and a steady growth process is proceeding in the interim. Implantation is a step of development, not of origin. The biology demonstrates that the point of origin of a unique human life is the formation of the zygote; which about half the time is of a different sex from his mother. Accordingly, once the principle is that innocent human life is respected, it is to be protected from outset. There is no non-arbitrary further point that is properly the beginning. That is the relevance and reason for the reference. KF