First, you make a self contradicting clause the basis for the rest of your lie: once fertilization happens, the 'thing' that is, is no longer an egg; people are not chickens.
Second, you want to float the popular leftist lie that even a mass of 150 or more cells of the new life in morulla stage descending the fallopian tube or inside the uterus but not implanted is 'undifferentiated. That lie is so smarmy I have addressed it twice for you on other threads, but still you try to use that lie here on this thread. You are a liar at heart is all I can discern about you from your continuing deceitful methodology.
Third, you want to blur the concept of form and function so that you can dismiss the earliest form and function of newly conceived living beings. You are a disgusting liar and it is likely we will witness on this thread the same sort of lying you've tried to push on other threads at FR.
You and your leftist ilk love to define the limits of forma nd function which you will allow to be acceptable for discussion. But it is a fact that you have to lie in order to try and float your leaky boats. You arbitrarily dismiss form and function occurring prior to the arbitrary point of magic personhood your evil ilk demand be the only perspective on gestational life. Freerepublic is a pro-life website. You are clearly not pro-life but you want to continue your charade. Why?
The blastocyst IS a mass of undifferentiated cells. At the most, cells might be polarizing, meaning that development pathways are being determined based on their position within the blastocyst--an automatic process completely driven by chemical signals. Differentiated cells actually do not grow, and typically die within a set time after differentiating, depending on tissue type. The process of differentiation is multi-step and continues until death of the organism.
That brings up another point--every tissue within your body, with one exception, has been completely replaced many times through the process of differentiation of new cells to replace the countless cells that die every single day. These new cells come from undifferentiated stem cells present throughout the body. The only exception is the nervous system. The various brain and neural cells do not die and are not replaced by new cells. They are the same cells you were born with, the same cells that started to differentiate three weeks after conception. The only continuity within your body is within the nervous system. You could say that the only purpose of the early embryo is to produce a brain, and the only purpose of the non-nervous system tissues after that is to support the brain.
Here is the Wikipedia article on human fertilization. And here is a figure from that article. Do me a favor, will you, study it and point out or describe to me the physical features of that pre-implantation embryo that enable it to be fully aware of and responsive to its environment through any process more sophisticated than spontaneous chemical responses to chemical and physical signals?
Once again, let me point out that I did not invent the events of early embryogenesis, I have merely described them. And providing accurate descriptions with the intent of educating people does *not* make me a liar or a leftist.