Now I'm in the when does life begin debate. This seems pretty straightforward.
"The American College of Pediatricians concurs with the body of scientific evidence that human life begins at conception - fertilization…. Scientific and medical discoveries over the past three decades have only verified and solidified this age-old truth. At the completion of the process of fertilization, the human creature emerges as a whole, genetically distinct, individuated zygotic living human organism, a member of the species homo sapiens, needing only the proper environment in order to grow and develop. The difference between the individual in its adult stage and in its zygotic stage is not one of personhood but of development. The Mission of the American College of Pediatricians is to enable all children to reach their optimal physical and emotional health and well-being from the moment of conception."
"After fertilization has taken place a new human being has come into being...[this] is no longer a matter of taste or opinion, it is not a metaphysical contention, it is plain experimental evidence...." -
Report, Subcommittee on Separation of Powers to Senate Judiciary Committee S-158, 97th Congress, 1st Session 1981
Longer read and has good info.
Pay attention to the first part that I bolded. Also, Myth 7 is a wall of text and not pasting that.
I. Introduction
The question as to when the physical material dimension of a human
being begins is strictly a scientific question, and fundamentally should be answered by human embryologists�
not by philosophers, bioethicists, theologians, politicians, x-ray technicians, movie stars, or obstetricians and gynecologists.
This part cuts to the chase.
Myth 1: "Prolifers claim that the abortion of a human embryo or a human fetus is wrong because it destroys human life. But human sperms and human ova are human life, too. So prolifers would also have to agree that the destruction of human sperms and human ova are no different from abortions�and that is ridiculous!"
Fact 1: As pointed out above in the background section, there is a radical difference, scientifically, between parts of a human being that only possess "human life" and a human embryo or human fetus that is an actual "human being." Abortion is the destruction of a human being. Destroying a human sperm or a human oocyte would not constitute abortion, since neither are human beings. The issue is not when does human
life begin, but rather when does the life of every human
being begin. A human kidney or liver, a human skin cell, a sperm or an oocyte all possess human
life, but they are not human
beings�they are only parts of a human being. If a single sperm or a single oocyte were implanted into a woman�s uterus, they would not grow; they would simply disintegrate.
Myth 2: "The product of fertilization is simply a �blob,� a �bunch of cells�, a �piece of the mother�s tissues�."
Fact 2: As demonstrated above, the human embryonic organism formed at fertilization is a whole human being, and therefore it is not just a "blob" or a "bunch of cells." This new human individual also has a mixture of both the mother�s and the father�s chromosomes, and therefore it is not just a "piece of the
mother�s tissues". Quoting Carlson:
"... [T]hrough the mingling of maternal and paternal chromosomes, the zygote is
a genetically unique product of chromosomal reassortment, which is important for the viability of any species."15 (Emphasis added.)
Myth 3: "The immediate product of fertilization is just a �potential� or a �possible� human being�not a real existing human being."
Fact 3: As demonstrated above, scientifically there is absolutely no question whatsoever that the immediate product of fertilization is a newly existing human being. A human zygote
is a human being. It is
not a "potential" or a "possible" human being. It�s an actual human being�with the potential to grow bigger and develop its capacities.
Myth 4: "A single-cell human zygote, or embryo, or fetus are not human beings, because they do not look like human beings."
Fact 4: As all human embryologists know, a single-cell human zygote, or a more developed human embryo, or human fetus is a human being�and that that�s the way they are supposed to look at those particular periods of development.
Myth 5: "The immediate product of fertilization is just an �it��it is neither a girl nor a boy."
Fact 5: The immediate product of fertilization is genetically already a girl or a boy�determined by the kind of sperm that fertilizes the oocyte. Quoting Carlson again:
"...[T]he sex of the future embryo is determined by the chromosomal complement of the spermatozoon. (If the sperm contains 22 autosomes and 2 X chromosomes, the embryo will be a genetic female, and if it contains 22 autosomes and an X and a Y chromosome, the embryo will be a genetic male.)"16
Myth 6: "The embryo and the embryonic period begin at implantation." (Alternative myths claim 14 days, or 3 weeks.)
Fact 6: These are a few of the most common myths perpetuated sometimes even within quasi-scientific articles�especially within the bioethics literature. As demonstrated above, the human embryo, who is a human being, begins at fertilization�not at implantation (about 5-7 days), 14-days, or 3 weeks. Thus the embryonic period also begins at fertilization, and ends by the end of the eighth week, when the fetal period begins. Quoting O�Rahilly:
https://www.princeton.edu/~prolife/articles/wdhbb.html