Taltimer posts:
Firstly, STUDY does not apply here, it is impossible to make a STUDY that will determine weather or not a zygote is a human being. Science involves many things, experiments, observation, classification, calculations, studies... and studies are the least valid and most error prone form of science, moreover they are completely impossible to apply to this simple yes no question.
Scientifically, this would be a matter of looking and understanding WHAT a human is, and then looking at the various stages of development and deciding "does this qualify". The most obvious options are: sperm/eggs, fertalized egg, implanted egg, moment of development of organ X (typically brian), birth, moment of development of conscious thought (which occurs after birth). So looking at it from a biological perspective a human is a colony of genetically identical cells which are each alive, they require each other for continued survival, but can survive removed from the body in the right conditions (replicated in a lab usually). Those cells form a colony, that is a multicellular organism, which has been named "human" and all the creatures it can cross breed with are considered to be of the same species.
Actually that study that you describe as impossible has already been done.
C. Ward Kischer, a human embryologist, explains it all very well ....He essentially says that not only science, but reason and common sense tells us that life begins with fertilization.
The case for fertilization of the human sperm/egg was made intuitively by observing the process in mammals more than 100 years ago. And direct observation of the process in the human was made in about 1968. The significance of this was resolved experimentally with subsequent growth of the new individual and successful implantation with completion of development to birth. This was accomplished with the birth of baby Louise Brown in England in July, 1978. Other successes soon followed.
The facts above,along with the constancy of the time of gestation, approx. 38 weeks, reasonably declare that the life of the new individual human being begins with fertilization. Virtually every human empbryologist and ever major textbook of Human Embryology state that fertilization marks the beginning of the life of the new individual human being.
The reason why this is true is the following:
from the moment when the sperm makes contact with the oocyte, under conditions we have come to understand and describe as normal, all subsequent development to birth of a living newborn is a fait accompli. That is to say, after that initial contact of spermatozoon and oocyte there is no subsequent moment or stage which is held in arbitration or abeyance by the mother, or the embryo or fetus. Nor is a second contribution, a signal or trigger, needed from the male in order to continue and complete development to birth. Human development is a continuum in which so - called stages overlap and blend one into another. Indeed, all of life is contained within a time continuum. Thus, the beginning of a new life is exacted by the beginning of fertilization, the reproductive event which is the essence of life.
Herein lies the importance of distinguishing between the science of developmental biology and the science of Human Embryology. Within the science of Human Embryology, the continuum of life is more fully appreciated. The fact that development and developmental principles do not cease with birth becomes more fully realized. So, the continuum of human development does not cease until death, whenever that may occur, in utero or at 100 years of age.
For the lay person it is not important to remember embryological terms, ....it is the continuum of life which is important as a biological fact......
When the sperm fuses with the secondary oocyte fertilization takes place. The fusion is referred to as a zygote, a single cell but with two pronuclei, each one containing either the maternal or the paternal chromosomes. The former are provided by the oocyte and the latter by the sperm. These pronuclei come together to reconstitute the proper number of chromosomes for our specie (called diploid), which is 46 chromosomes, including 2 sex chromosomes. From this coming together the single cell divides into two cells, and division continues until a cluster or ball of cells is formed called the morula. Soon thereafter, the cells in the morula divide and cluster so that a small cavity is formed, above which is a mass of cells. This is called the blastula, and when the cavity becomes larger the embryo is called the blastocyst and the mass of cells above it is called the inner cell mass or the ICM. Other events have taken place since fertilization, especially movement of the embryo down the fallopian tube, assumming fertilization has taken place in the upper third of the tube, which is optimal, so that the embryo is positioned properly within the uterus and ready for implantation. This takes 5 to 6 days. The outer rim of cells of the embryo has special properties allowing it to "invade" the lining of the uterus. Among the many simultaneous events occurring are changes in the cells of the embryo which "regulate" its destiny. Such regulation actually began at probably the first cell division of the embryo when an unusual but significant production of an immunosuppresant takes place, the early pregnancy factor. This prevents rejection of the "foreign" embryo by the mother.
In addition, the "regulation" taking place among the cells of the early embryo has to do with communications between the cells, which allow for movement of materials, providing signals or directions to a cell or cells prompting them to divide or not to divide, or to respond in general or specific ways which can direct their destiny or potentials.
One often hears the rallying cry from prochoice advocates: "my body, my choice". Certainly, they exercise a choice, but, it is not just "my body". There are two bodies, each genetically distinct, and each "foreign" to the other. It should be recognized that the body of the early embryo is very active in its daily rituals of survival.
Every moment of development blends into the next succeeding moment. But, even common sense tells one that this so-called development does not cease at birth. It continues until death. At any point in time, during the continuum of life, there exists a whole, integrated human being. This is because over time from fertilization to a 100 year old senior, all of the characteristics of life change, albeit at different rates at different times: size, form, content, function, appearance, etc.
Pregnancy
Human embryologist Bruce Carlson, in his 1994 textbook: "Human Embryology and Developmental Biology", states in his opening sentence: "Human pregnancy begins with the fusion of the egg and the sperm. . ."[2]. This is so because the concern of Human Embryology is the human embryo whether it be in the fallopian tube, uterus, ectopically placed or in a petri dish. Additionally, for a pregnant woman, the expected time of delivery, fertilization age, time of gestation, or, the period of confinement is always calculated so that the time of pregnancy begins at fertilization.
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Scientists in the fields of genetics, biology and human embryology have done their jobs well. It's just that some have turned science into political correctness and human life and all its elements have been/is being manipulated by those with the attitude that "abortion on demand" must be kept "legalized" at all costs.
