Thanks for providing that. I asked because the statistics you provided seemed really high. Unfortunately, the link you provided does not affirm what you said.
You:
1)About 50% of fertilized eggs don't successfully implant on the uterine wall, and
2)about 50% of those will result in miscarriages
Source:
1)Up to 50% of all fertilized eggs may spontaneously abort
2)Women who know they are pregnant have a miscarriage rate of 15-20%
Things worth noting would be that the 50% number includes both women who know they are pregnant and women who do not know they are pregnant.
The question that I walk away most from this though is how exactly do doctors have any sort of idea of the percentage of fertilized eggs that spontaneously abort
without a woman ever knowing she was pregnant? Doesn't the fact that the woman doesn't know mean that we wouldn't be able to produce a statistic on that?
Now, as for Douglas... Here's a good educational read for him:
Human development begins at fertilization, the process during which a male gamete or sperm ... unites with a female gamete or oocyte ... to form
a single cell called a zygote.
This highly specialized, totipotent cell marks the beginning of each of us as a unique individual.
4 (emphases added)
In this text, we begin our description of the developing human with the formation and differentiation of the male and female sex cells or gametes, which will unite at fertilization to initiate the embryonic development of
a new individual.
5 (emphases added)
... Coalescence of homologous chromosomes,
resulting in a one-cell embryo. ... The
zygote is characteristic of the last phase of fertilization and is identified by the first cleavage spindle. It
is a unicellular embryo and is a highly specialized cell. (p. 33) ... t is now accepted that the word
embryo, as currently used in human embryology, means
'an unborn human in the first 8 weeks' from fertilization.
6 (emphases added)
In multi-cellular organisms, each of the cells that comprise it are only "parts" of that whole being. An organism is inherently capable of its growth and reproduction as a being; a cell can only multiply more cells, not more beings (unless they are totipotent, separated from the whole organism, and the state of differentiation of their DNA is reversed to "zero" by the process of "regulation" - the basis of cloning by "twinning".
7).
Rahilly addresses "human organisms", their distinction from just "cells", and their growth and development in his first chapter dealing with the science of human embryology. As Rahilly documents, the immediate product of human sexual reproduction is a single-cell organism:
Although life is a continuous process, fertilization ... is a critical landmark because, under ordinary circumstances,
a new, genetically distinct human organism is formed when the chromosomes of the male and female pronuclei blend in the oocyte. This remains true even though the embryonic genome is not actually activated until 2-8 cells are present at about 2-3 days.
8 (emphases added)
It is precisely because the immediate product is an
organism that the international Nomina Embryologica Committee formally rejected the fake term "pre-embryo". As Rahilly put it:
(4) it [the term "pre-embryo"] is equivocal because it may convey
the erroneous idea that a newhuman organism is formed at only some considerable time after fertilization;
9 (emphases added)
Rather, the
single-cell human organism - the human being, human embryo, human individual - simply then proceeds to grow bigger:
Human embryology ... is the study of the human embryo and fetus. ... Development includes growth (an increase in the mass of tissue) and differentiation, by which is meant increasing complexity. Although early development, particularly that of the embryo, is the main focus of embryology, development continues after birth as well as before. ... Development is under the control of the genome, which operates at several levels of organization. A reductionist approach, however, needs to be complemented by descriptive embryology so that the end products of genetic and environmental interaction, mainly organs and systems, can be clearly discerned. (p. 7) ... Growth, strictly speaking, is an increase in the size of
an organism or of its parts. ... The chief cause of prenatal growth is cellular division. Growth is ordinarily accompanied by the specialized cellular changes that constitute differentiation. Although growth is very marked prenatally and during the first two decades postnatally,
it continues throughout life.
10(emphases added)
4 Keith Moore and T. V. N. Persaud, The Developing Human: Clinically Oriented Embryology (6th ed. only) (Philadelphia: W.B. Saunders Company, 1998), p. 18.
5 William J. Larsen, Human Embryology (New York: Churchill Livingstone, 1997), p. 1.
6 Ronan O'Rahilly and Fabiola Muller, Human Embryology & Teratology (New York: Wiley-Liss, 2001), p. 87.
7 For a scientific explanation (with extensive scientific references) of the role of "regulation" in both sexual and asexual reproduction, see Irving, "Playing God by manipulating man: Facts and frauds of human cloning" (October 4, 2003), presented twice at the Missouri Catholic Conference Annual Assembly Workshop, Jefferson City, MO, at:
http://www.mocatholic.org/uploads/IrvingCloning3.pdf, and at
http://www.lifeissues.net/writers/irv/irv_22manipulatingman1.html; see also "Stem cells that could become embryos: Implications for the NIH Guidelines on stem cell research, the NIH stem cell report, informed consent, and patient safety in clinical trials" (July 22, 2001); written as consultant on human embryology and human embryo research as Fellow of The Linacre Institute (CMA), The Catholic Medical Association (USA), and The International Federation of Catholic Medical Associations (FIAMC), at:
http://www.lifeissues.net/writers/irv/irv_39anlystemcel1.html.
8 Ronan O'Rahilly and Fabiola Muller, Human Embryology & Teratology (New York: Wiley-Liss, 2001), p. 31.
9 Ibid., p. 88.
10 Ibid, p. 98