Always remember!
Posted on 02/02/2009 8:23:19 PM PST by cpforlife.org
You should take your two copper coins and invest in some books on human developmental biology. The child begins to act as an individual human being within seconds after sperm entering the egg beginning with an immediate thickening of the egg wall denying entry of antoher sperm.
Your idea that conception takes 16 to 18 days brings your abject ignorance of developmental biology into sharp relief.
The child begins to act as an individual human being within seconds after sperm entering the egg beginning with an immediate thickening of the egg wall denying entry of antoher sperm.
It's a triggering mechanism from the sperm cell's acrosomal cap that causes the egg's membrane to deny entry of other sperm. The father's DNA has had no role to play at this time, and the fusion is not yet an individual (the chromosomes haven't yet paired).
http://en.wikipedia.org/wiki/Gastrulation
In mammals, gastrulation occurs after implantation, around day 16 after fertilization in human embryogenesis. As the outer cell mass invades the endometrium, the inner cell mass divides into two layers: the epiblast and hypoblast. The hypoblast spreads out and covers the blastocoel to form the yolk sac. The yolk sac is an extraembryonic tissue that produces blood cells similar to the structure that surrounds the yolk in birds. The epiblast further divides into two more layers. The amnion layer forms the fluid filled cavity to surround and protect the embryo during pregnancy. The embryonic epiblast undergoes gastrulation.
Gastrulation, which occurs around 16 days after fertilisation, is the point in development when the implanted blastocyst develops three germ layers, the endoderm, the ectoderm and the mesoderm. It is at this point that the genetic code of the father becomes fully involved in the development of the embryo. Until this point in development, twinning is possible. Additionally, interspecies hybrids survive only until gastrulation, and have no chance of development afterward.
And exactly why do you believe that gastrulation marks anything beyond another stage of development. You clearly don’t understand the topic and are grasping at wiki straws. Here are some references from medical school textbooks used to teach the subjects of embryology, fetology, developmental biology, and OB/Gyn and highly respected, peer reviewed medical journals. They are quite explicit with regard to when an individual human being’s life begins.
“Often,this morula is inaccurately referred to as a ‘fertilized egg’ because the blastomeres remain inside the female parent’s oocyte outer cell membrane. That is an incorrect characterization, because the 23 -chromosome oocyte no longer exists; all the cells within the morula have the unique genome—46 chromosomes and a complement of mitochondrial DNA —of the newly conceived individual life.” Moore and Persaud, The Developing Human, 6th ed., (p. 43)
“the proposition that an unborn child is a human being from conception is “supported by standard textbooks on embryology or human biology”T.W. SADLER, LANGMAN’S MEDICAL EMBRYOLOGY (John N. Gardner ed., 6th ed.
“Fertilization is an important landmark because, under ordinary circumstances, a new, genetically distinct human being is thereby formed... The zygote is a unicellular human being... Ronan R. O’Rahilly, Fabiola Muller, (New York: Wiley-Liss), 5, 55. EMBRYOLOGY & TERATOLOGY
“Every time a sperm cell and ovum unite a new human being is created which is alive and will continue to live unless its death is brought about by some specific condition.”E.L. Potter and J.M. Craig, PATHOLOGY OF THE FETUS AND THE INFANT, 3d ed. (Chicago: Year Book Medical Publishers, vii.
“Physicians, biologists, and other scientists agree that conception marks the beginning of the life of a human being—a being that is alive and is a member of the human species. There is overwhelming agreement on this point in countless medical, biological, and scientific writings.” John C. Fletcher, Mark I. Evans, “Maternal Bonding in Early Fetal Ultrasound Examinations,” New England Journal of Medicine, February 17, 1983.
Now do feel free to provide some equally credible sources that state explicitly that the offspring of two human beings is EVER anything other than a human being.
Does the genetic makeup of the fertilized egg alter at any stage past the immediate point of entry of the sperm, into the egg? Is the genetic arrangement of the fused gametes final, before gastrulation?
Without a unique DNA, you don’t have an individual.
As I said, do feel free to provide some equally credible material that states explicitly that the offspring of two human beings is ever anything but a human being.
Railing against credible material with nothing more than your opinion is the act of a flat earther. If it is true that unborns in the early stage of development are something other than living human beings, you should have no problem at all providing at least as much credible reference material to me as I have provided to you.
Good luck. You may as well be trying to prove that the moon is made of cheese.
By the way, a zygote has unique DNA.
Not to mention that I don't know why you're asking the above, you did not answer my previous query, which, in itself, was asked about several days ago.
Your previous post has no mention of the processes leading up to gastrulation, nor does it mention anything about how long it takes for the father's genetic material to combine fully with the mother's. I stated that (from the WiKi article, which has a citation link, which also happens to be where you sourced the material for your earlier post) the genetic material from the sperm hasn't completed combination with that from the mother until the 16th day. This is an important distinction because only after the genetics of the offspring is determined, will it be capable of being considered an individual.
I should have clarified this in my previous post, that your earlier post didn't answer what was argued a couple of days ago, but this should suffice.
By the way, a zygote has unique DNA.
This was not the argument. The argument was revolving around when the father's genes have completed involving themselves with those of the mother's. Just the entry of the sperm into the egg, isn't the instant when an individual is genetically determined.
Citation: Moore, K. L. & T. V. M. Persaud (2003). The Developing Human: Clinically Oriented Embryology. W. B. Saunders Company. ISBN 0-7216-6974-3.
If you have access to a journal, perhaps you can look it up. I don't, for now.
At the point where the surface of the egg changes and no other sperm can enter, yes, it is the instant when an individual is genetically determined. It similar to if someone pushed you off of a very tall building. At the point where you can no longer be pulled back or hang on and start falling unstoppably to the ground is the point at which your death is determined, even if you don't actually die until you hit the pavement below. It's also why pushing you off of the building would be considered murder, even though the push and the fall didn't kill you, the sudden deceleration at the end did.
Of course this whole objection is entirely irrelevant because the distinction you are looking for matters only if someone were to hover above an egg as it was being fertilized and were to destroy it between the point the first sperm entering the egg and the comination of the genetic material from sperm and egg. This will never happen in practice and is thus irrelevant, just as the determining the point at which you'd actually die if you fell to the ground from a high height between the moment when the first part of your body hit the ground and the point where your remains where liquified and distributed across a broad area is irrelevant because nobody is going to every stop that process in the middle in a way where it will matter. This is the classic post-modern strategy to dismissing anything. Insist on looking only at the trees and then claim the forest doesn't exist.
Tell that to thousands of identical twins. There are also plenty of science fiction thought experiments to the contrary (e.g., the Star Trek episodes where a person is split into two people by a transporter accident).
“the genetic material from the sperm hasn’t completed combination with that from the mother until the 16th day”
Sorry, but that simply is not true. A zygote, at the single cell stage has unique DNA, a full compliment of 46 chromosomes that idenitify it as a unique individual. Combination of DNA is complete before the first division begins. The zygote is a totipotent cell and its unique DNA signature is carried forth in every division from that point forward.
Do feel free to provide some credible science that states explicitly that the offspring of two human beings is ever anything but a human being.
Encyclopædia Britannica, 2009.
Search under 'Gastrulation' in the article on animal development.
Sorry guy, but you clearly don’t understand what you are talking about. That only says that there is a period where maternal genes are influential and at the end of that period, paternal genes also come into play. The unique DNA of the child exists from the time fertilization is comlete. The zygote is a unique individual human being.
Once more, do feel free to provide some credible material that states explictly that the offspring of two human beings is EVER anything but a living human being.
It was nearly effortless for me to provide several credible sources that state explictly that we are indeed living human beings from the time we are concieved. In fact, one states clearly that a zygote is a unicellular human being.
By now, it should be clear to you that you are not going to find anything that suggests that unborns, even at the very early stages are something other than living human beings, but by all means, keep reaching for straws. There is a certain facination to be found in your efforts.
In contrast to the genetic view, the embryological view states that human life originates not at fertilization but rather at gastrulation. Human embryos are capable of splitting into identical twins as late as 12 days after fertilization resulting in the development of separate individuals with unique personalities and different souls, according to the religious view. Therefore, properties governing individuality are not set until after gastrulation. This view is endorsed by a host of contemporary scientists such as Renfree (1982), Grobstein (1988) and McLaren. This view of when life begins has also been adopted as the official position of the British government. The implications of a belief in this view include giving support to controversial forms of contraception including the "morning after" pill and contragestational agents as long as they are administered during the first two weeks of pregnancy.
One of the most popular positions among philosophers is the perspective that life begins at the point of gastrulation - that point at which the zygote is an ontological individual and can no longer become two individuals. Gastrulation commences at the beginning of the third week of pregnancy, when the zygote, now known as an embryo, is implanted into the uterus of the mother. The cells are now differentiated into three categories that will give rise to the different types of body tissue. (Shannon and Wolter 1990). After gastrulation the zygote is destined to form no more than one human being.
The philosophers who support this position argue that there exists a difference between a human individual and a human person. A zygote is both human and numerically single and thus a human individual. However, because individuality is not certain until implantation is complete, and because individuality is a necessary condition of personhood, the zygote is not yet a human person. (Ford 1988; Shannon and Wolter 1990; McCormick 1991). Catholic scholars Shannon and Wolter (1990) describe this eloquently saying, "An individual is not an individual, and therefore not a person, until the process of restriction is complete and determination of particular cells has occurred. Then, and only then, it is clear that another individual cannot come from the cells of this embryo."
Some supporters of the fertilization position find fault in this argument by claiming that the potential of twinning is a technicality and not strong enough to support the claim that human life does not begin until gastrulation. Alan Holland puts forth the view that just because a zygote has the possibility to divide into multiple individuals does not mean that it is not an individual before it divides. As an analogy, he presents the case of the worm that is clearly a single individual worm until it is cut into two when it becomes two individual worms. (Holland 1990).
Some would also argue that in the discussion of when human life begins the question of whether a zygote will eventually become one individual or multiple individuals is irrelevant. The key point is that at least one human life may begin as the result of the zygote, and thus human life began at the creation of the zygote, fourteen days before gastrulation.
http://8e.devbio.com/article.php?id=162
Once more, do feel free to provide some credible material that states explictly that the offspring of two human beings is EVER anything but a living human being.
Read my post prior to my immediate previous post.
No credible science to support your position huh? Not to worry, I knew that you couldn’t find any. I knew that before I ever issued the challenge.
What do you suppose it means that identical twins can result up to 12 days after fertilization? I can tell you in a flash, and it doesn’t mean that early unborns are not living human beings. It simply means that for a very short time, human beings are capable of asexual reproduction and nothing more.
You are grasping at straws and any argument you put forward that something other than a living human being exists after fertilization is complete will fail because science simply doesn’t support you.
The fact that there is a chain of events with possible variations during our maturation process in no way proves that we are not living human beings from the very beginning.
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