I think you are making a distinction without a difference. What is that being? It is a new human being. The beginning of the life of the new human being. These quotes are not saying its in a pre human being stage developing into a human being... they are saying its a new human being.
here are 2 more of the multiple quotes...
The Developing Human: Clinically Oriented Embryology, 6th ed. Keith L. Moore, Ph.D. & T.V.N. Persaud, Md., (Philadelphia: W.B. Saunders Company, 1998), 2-18:
“[The Zygote] results from the union of an oocyte and a sperm. A zygote is the beginning of a new human being. Human development begins at fertilization, the process during which a male gamete or sperm … unites with a female gamete or oocyte … to form a single cell called a zygote. This highly specialized, totipotent cell marks the beginning of each of us as a unique individual.”
Scarr, S., Weinberg, R.A., and Levine A., Understanding Development, Harcourt Brace Jovanovich, Inc., 1986. page 86
“The development of a new human being begins when a male’s sperm pierces the cell membrane of a female’s ovum, or egg….The villi become the placenta, which will nourish the developing infant for the next eight and a half months.”
Jem, you can quote all day long every day until you die. Your quotes all say the same thing: Human being development begins...etc. And for the last time, none of that is being debated. It doesn't change the fact that a single/multi cellular organism isn't the same thing as a human being - even if they are genetically identical under a microscope. A human being is more than just a few cells. End of story.
