Your quote is not from the medical embryology textbook used. Here is a Moore quote from the 7th edition of The Developing Human: Clinically Oriented Embryology: "‘‘Human development begins at fertilization when a male gamete or sperm (spermatozoon) unites with a female gamete or oocyte (ovum) to produce a single cell, a zygote. This highly specialized, totipotent cell marked the beginning of each of us as a unique individual.’’
The 9th edition (with a third author, Torchia) of the textbook is available in PDF for free download. I'm not willing to install a downloader because I've read that they're the devil to remove, but if you Google, you can find at least two sites that provide access if you're willing.
As for the textbooks used by the top ten med schools, all you have to do is Google "______ medical school embryology courses and textbooks."
So your reason for discounting an embryology textbook, written by the same authors of a different embryology textbook which you
will accept, is that it isn't specifically listed on the reading list of ten particular universities?
Seems to me like you're going to great lengths to try and discredit a source that disagrees with you.
As for your quote above, it doesn't say what you are implying it says. As I mentioned earlier in this thread, there's a big difference between "beginning the development of" or "being the beginning of" something and actually
being it. The analogies are endless - but the standard one is that (tailored to analogise your above quote) "The development of a cake begins when the first ingredients are mixed, producing the cake mixture. This delicious goop marks the beginning of a cake as a tasty treat". And yet a cake mixture is not yet a cake - it is merely the beginning of one.
Since you are specifically naming certain books, though... Some other quotes from
The Developing Human for you (I used the ninth edition, since that seems to be the most recent one available):
"Cell division, cell migration, programmed cell death, differentiation, growth, and cell rearrangement transform the fertilized oocyte, a highly specialised, totipotent cell, a zygote, into a multicellular human being" ~p1
"The zygote divides many times and becomes progressively transformed into a multicellular human being through cell division, migration, growth and differentiation." ~p13
Oh, and while I'm here, one from
Langman's Medical Embryology:
"From a single cell to a baby in nine months; a developmental process that represents an amazing integration of increasingly complex phenomena. The study of these phenomena is called embryology, and the field includes investigations of the molecular, cellular, and structural factors contributing to the formation of an organism" ~pxii