When do human beings begin?
Scientific myths and scientific facts
Dianne N. Irving, M.A., Ph.D.
Professor of Philosophy
Dominican House of Studies
Washington, D.C. 20017
[Note: This article was originally published in "Abortion and Rights," a
special edition of the International Journal of Sociology and Social Policy,
edited by Doris Gordon and John Walker of Libertarians for Life (Vol. 19,
No. 3/4, 1999, Barmarick Publications, England). All the articles in
"Abortion and Rights" can be read on LFL's
The question as to when a human being begins is strictly a scientific question,
and should be answered by human embryologists - not by philosophers,
bioethicists, theologians, politicians, x-ray technicians, movie stars or
obstetricians and gynecologists. Current discussions on abortion, human embryo
research (including cloning, stem cell research and the formation of
mixed-species chimeras) and the use of abortifacients involve specific claims
as to when the life of every human being begins. The purpose of this article
is to focus directly on just some of the "scientific" myths, and on the objective
scientific facts that ought to ground these discussions. At least it will
clarify what the actual international consensus of human embryologists is
with regard to this relatively simple scientific question. If the "science"
used to ground these various discussions is incorrect, then any conclusions
will be rendered groundless and invalid.
II. Brief background on the accurate human embryological facts:
Understanding just a few basic human embryological terms accurately can
considerably clarify the drastic difference between the "scientific" myths
that are currently circulating throughout the literature, and the actual
objective scientific facts. This would include such basic terms as:
"gametogenesis," "oogenesis," "spermatogenesis," "fertilization," "zygote,"
"embryo" and "blastocyst." Only brief scientific descriptions will be given
here for these terms. Further, more complicated, details can be obtained
by investigating any well-established human embryology textbook in the library,
such as some of those referenced below. Please note that the scientific facts
presented here are not simply a matter of my own opinion. They are direct
quotes and references from some of the most highly respected human embryology
textbooks, and represent a consensus of human embryologists internationally.
To begin with, scientifically something very dramatic occurs between the
processes of gametogenesis and fertilization - the change from two simple
PARTS of a human being, i.e., a sperm and an oocyte (usually referred to
as an "ovum" or "egg"), which simply possess "human life" into a new, genetically
unique, newly existing, individual, live human BEING, an embryonic single-cell
human zygote. That is, parts of a human being have actually been transformed
into something very different from what they were before; they have been
changed into a single, whole human being. During this process, the sperm
and the oocyte cease to exist, and a new human being is produced.
To understand this, it is already known that each kind of living organism
has a specific number and quality of chromosomes which are characteristic
for each member of a species (the number can vary only slightly if the organism
is to survive). For example, the characteristic number of chromosomes for
a member of the human species is 46 (plus or minus, e.g., in human beings
with Down or Turner's syndromes). Every somatic cell in a human being has
this characteristic number of chromosomes, including the sex gametes - the
sperm and the oocyte. Sperms and oocytes are derived from primitive germ
cells in the developing fetus by means of the process known as "gametogenesis."
Because each gamete normally has 46 chromosomes, the process of "fertilization"
can not take place until the total number of chromosomes in each gamete are
cut in half. This is necessary so that after their fusion at fertilization
the characteristic number of chromosomes in a single individual member of
the human species (46) can be maintained. To accurately see why a sperm or
an oocyte are considered as only possessing human life, and not as human
beings themselves, one need look at the basic scientific facts involved in
the processes of gametogesesis and of fertilization.
As the human embryologist Larsen states it, gametogenesis is the process
that converts primordial germ cells (primitive sex cells) into mature sex
gametes - in the male (spermatozoa, or sperms), and in the female (definitive
oocytes). The timing of gametogenesis is different in males and in females.
Spermatogenesis in males begins at puberty, and continues throughout adult
life. The process involves the production of spermatogonia from the primitive
germ cells, which in turn become primary spermatocytes, and finally spermatids
- or mature spermatozoa (sperms). These mature sperms will have only half
of the number of their original chromosomes - i.e., the number of chromosomes
has been cut from 46 to 23, and therefore they are ready to take part in
Oogenesis begins in the female during fetal life. The total number of primary
oocytes - about 7 million - is produced in the female fetus' ovaries by 5
months of gestation in the mother's uterus. By birth, only about 700,000
- 2 million remain. By puberty, only about 400,000 remain. The process involves
the production of oogonia from primitive germ cells, which in turn become
primary oocytes, which become definitive oocytes only at puberty. This definitive
oocyte is what is released each month during the female's menstrual period,
but it still has 46 chromosomes. In fact, it does not reduce its number of
chromosomes until and unless it is fertilized by the sperm, during which
process the definitive oocyte becomes a secondary oocyte with only 23
This halving of the number of chromosomes in the gametes takes place by the
process of meiosis. Many people confuse meiosis with a different process
known as mitosis, but there is an important difference. Mitosis involves
the normal division of a somatic, or body, cell in order to increase the
number of those cells during growth and development. The resulting cells
contain the same number of chromosomes as the previous cells - in human beings,
46. Meiosis involves the halving of the number of chromosomes which are normally
present in a somatic cell (here, in the sex gametes - the precursors of the
sperm and the definitive oocyte) in order for fertilization to take place.
The resulting cells have only half of the number of chromosomes as the previous
cells - in human beings, 23
One of the best and most technically accurate explanations for this critical
process of gametogenesis is by Ronan O'Rahilly, the human embryologist who
developed the classic Carnegie stages of human embryological development.
He also sits on the international board of Nomina Embryologica (which determines
the correct terminology to be used in human embryology textbooks
Gametogenesis is the production of [gametes], i.e., spermatozoa and oocytes.
These cells are produced in the gonads, i.e., the testes and ovaries
During the differentiation of gametes, diploid cells
(those with a double set of chromosomes, as found in somatic cells [46
chromosomes]) are termed primary, and haploid cells (those with a single
set of chromosomes [23 chromosomes]) are called secondary. The reduction
of chromosomal number
from 46 (the diploid number or 2n) to 23 (the
haploid number or n) is accomplished by a cellular division termed meiosis.
Spermatogenesis, the production of spermatozoa, continues from immediately
after puberty until old age. It takes place in the testis, which is also
an endoctrine gland, the interstitial cells of which secrete testosterone.
Previous to puberty, spermatogonia in the simiferous tubules of the testis
remain relatively inactive. After puberty, under stimulation from the
interstitial cells, spermatogonia proliferate
and some become primary
spermatocytes. When these undergo their first maturation division (meiosis
1), they become secondary spermatocytes. The second maturation division (meiosis
2) results in spermatids, which become converted into spermatozoa."
Oogenesis is the production and maturation of oocytes, i.e.; the female gametes
derived from oogonia. Oogonia (derived from primordial germ cells) multiply
by mitosis and become primary oocytes. The number of oogonia increases to
nearly seven million by the middle of prenatal life, after which it diminishes
to about two million at birth. From these, several thousand oocytes are derived,
several hundred of which mature and are liberated (ovulated) during a
reproductive period of some thirty years. Prophase of meiosis 1 begins during
fetal life but ceases at the diplotene state, which persists during childhood.
After puberty, meiosis 1 is resumed and a secondary oocyte
is formed, together with polar body 1, which can be regarded as an oocyte
having a reduced share of cytoplasm. The secondary oocyte is a female gamete
in which the first meiotic division is completed and the second has begun.
From oogonium to secondary oocyte takes from about 12 to 50 years to be
completed. Meiosis 2 is terminated after rupture of the follicle (ovulation)
but only if a spermatozoon penetrates.
The term "ovum" implies that
polar body 2 has been given off, which event is usually delayed until the
oocyte has been penetrated by a spermatozoon (i.e., has been fertilized).
Hence a human ovum does not [really] exist. Moreover the term has been used
for such disparate structures as an oocyte and a three-week embryo, and therefore
should be discarded, as a fortiori should "egg." (emphasis added)
Thus, for fertilization to be accomplished, a mature sperm and a mature human
oocyte are needed. Before fertilization, each has only 23 chromosomes. They
each possess "human life," since they are parts of a living human being;
but they are not each whole living human beings themselves. They each have
only 23 chromosomes, not 46 chromosomes - the number of chromosomes necessary
and characteristic for a single individual member of the human species.
Furthermore, a sperm can produce only "sperm" proteins and enzymes; an oocyte
can produce only "oocyte" proteins and enzymes; neither alone is or can produce
a human being with 46 chromosomes.
Also, note O'Rahilly's statement that the use of terms such as "ovum" and
"egg" - which would include the term "fertilized egg" - is scientifically
incorrect, has no objective correlate in reality, and is therefore very
misleading - especially in these present discussions. Thus these terms themselves
would qualify as "scientific myths." The commonly used term, "fertilized
egg," is especially very misleading, since there is really no longer an egg
(or oocyte) once fertilization has begun. A "fertilized egg" is a human being.
Now that we have looked at the formation of the mature haploid sex gametes,
the next important process to consider is fertilization. O'Rahilly defines
"the procession of events that begins when a spermatozoon makes contact
with a secondary oocyte or its investments, and ends with the intermingling
of maternal and paternal chromosomes at metaphase of the first mitotic division
of the zygote. The zygote is characteristic of the last phase of fertilization
and is identified by the first cleavage spindle. It is a unicellular embryo.
The fusion of the sperm (with 23 chromosomes) and the oocyte (with 23
chromosomes) at fertilization results in a live human being, a single-cell
human zygote, with 46 chromosomes - the number of chromosomes characteristic
of an individual member of the human species. Quoting Moore:
Zygote: This cell results from the union of an oocyte and a sperm. A zygote
is the beginning of a new human being (i.e., an embryo). The expression
fertilized ovum refers to a secondary oocyte that is impregnated by a sperm;
when fertilization is complete, the oocyte becomes a zygote. (emphasis added)
This new single-cell human being immediately produces specifically human
proteins and enzymes (not carrot or frog enzymes and proteins), and directs
his/her own growth and development (in fact this growth and development has
been proven not to be directed by the mother). Finally, this new human being
- the single-cell human zygote - is biologically an individual, a living
organism - an individual member of the human species. Quoting Larsen:
"[W]e 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."
In sum, a human sperm and a human oocyte are products of gametogenesis -
each has only 23 chromosomes. They each have only half of the required number
of chromosomes for a human being. They cannot singly develop further into
human beings. They produce only "gamete" proteins and enzymes. They do not
direct their own growth and development. And they are not individuals, i.e.,
members of the human species. They are only parts - each one a part of a
human being. On the other hand, a human being is the immediate product of
fertilization. As such he/she is a single-cell embryonic zygote, an organism
with 46 chromosomes, the number required of a member of the human species.
This human being immediately produces specifically human proteins and enzymes,
directs his/her own further growth and development as human, and is a new,
genetically unique, newly existing, live human individual.
After fertilization the single-cell human embryo doesn't become another kind
of thing. It simply divides and grows bigger and bigger, developing through
several stages as an embryo over an 8-week period. Several of these developmental
stages of the growing embryo are denoted as a morula (about 4 days), a blastocyst
(5-7 days), a bi-laminar (two layer) embryo (during the second week), and
a trilaminar (3-layer) embryo (during the third week).
III. "Scientific myths" and scientific facts:
Given these basic facts of human embryology, it is easier to recognize the
many scientifically inaccurate claims that have been advanced in the discussions
about abortion, human embryo research, cloning, stem cell research, the formation
of chimeras, and the use of abortifacients - and why these discussions obfuscate
the objective scientific facts. The following is just a sampling of some
of these current "scientific myths."
MYTH 1: "Pro-lifers 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 pro-lifers would also have to say that the destruction
of human sperms and human ova are abortions too - and that is ridiculous!"
FACT 1: As pointed out above in the background section, there is quite a
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 simply rot. They would not
grow as human embryos or human fetuses who are human beings.
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. (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.
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 which fertilizes the oocyte. Quoting
...[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.)
MYTH 6: "The embryo and the embryonic period begin at: implantation; 14 days;
FACT 6: These are several 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:
Prenatal life is conveniently divided into two phases: the embryonic and
the fetal. The embryonic period proper during which the vast majority of
the named structures of the body appear, occupies the first 8 postovulatory
weeks. ... the fetal period extends from 8 weeks to birth ... (emphasis added)
MYTH 7: "The product of fertilization, up to 14-days, is not an embryo; it
is just a 'pre-embryo' - and therefore it can be used in experimental research,
aborted or donated."
FACT 7: This scientific myth is perhaps the most common error, which pervades
the current literature. The term "pre-embryo" has quite a long and interesting
history (see Irving and Kischer, The Human Development Hoax: Time To Tell
The Truth! for extensive details and references), but it roughly goes back
to at least 1979 in the bioethics writings of Jesuit theologian Richard McCormick
in his work with the Ethics Advisory Board to the United States Department
of Health, Education and Welfare, and those of frog developmental biologist
Dr. Clifford Grobstein in a 1979 article in Scientific American, and most
notably in his classic book, Science and the Unborn: Choosing Human Futures
(1988). Both McCormick and Grobstein subsequently continued propagating this
scientific myth as members of the Ethics Committee of the American Fertility
Society, and in numerous influential bioethics articles, leading to its common
use in bioethics, theological, and public policy literature to this day.
The term "pre-embryo" was also used as the rationale for permitting human
embryo research in the British Warnock Committee Report (1984), and then
picked up by literally hundreds of writers internationally, including e.g.,
Australian writers Michael Lockwood, Michael Tooley, Alan Trounson - and
especially by Peter Singer (a philosopher), Pascal Kasimba (a lawyer), Helga
Kuhse (an ethicist), Stephen Buckle (a philosopher) and Karen Dawson (a
geneticist, not a human embryologist). Note that none of these is even a
scientist, with the exception of Karen Dawson, who is just a geneticist.
Oddly, their influential book, Embryo Experimentation, (which uses the term
"pre-embryo," and which contains no scientific references for its "human
embryology" chart or its list of "scientific terms), along with the work
of theologian McCormick and frog developmental biologist Grobstein, was used
in the United States as the scientific basis for the 1994 NIH Human Embryo
Research Report. That Report concluded that the "preimplantation embryo"
(they too originally used the term "pre-embryo") had only a "reduced moral
status." (Both the Warnock Report and the NIH Report admitted that the 14-day
limit for human embryo research was arbitrary, and could and must be changed
if necessary). It is particularly in the writings of these and other bioethicists
that so much incorrect science is claimed in order to "scientifically" ground
the "pre-embryo" myth and therefore "scientifically" justify many of the
issues noted at the beginning of this article. This would include abortion,
as well as the use of donated or "made-for-research" early human embryo in
destructive experimental human embryo research (such as infertility research,
cloning, stem cell research, the formation of chimeras, etc.).
To begin with, it has been demonstrated above that the immediate product
of fertilization is a human being with 46 chromosomes, a human embryo, an
individual member of the human species, and that this is the beginning of
the embryonic period. However, McCormick and Grobsteinclaim that even though
the product of fertilization is genetically human, it is not a "developmental
individual" yet - and in turn, this "scientific fact" grounds their moral
claim about this "pre-embryo." Quoting McCormick:
I contend in this paper that the moral status - and specifically the
controversial issue of personhood - is related to the attainment of developmental
individuality (being the source of one individual) ... It should be noted
that at the zygote stage the genetic individual is not yet developmentally
single - a source of only one individual. As we will see, that does not occur
until a single-body axis has begun to form near the end of the second week
post fertilization when implantation is underway. (emphasis added)
Sounds very scientific. However, McCormick's embryology is already
self-contradictory. The "single body axis" to which he refers is the formation
of the primitive streak which takes place at 14 days. Implantation takes
place at 5-7 days. McCormick often confuses these different periods in his
writings. But McCormick continues:
This multicellular entity, called a blastocyst, has an outer cellular wall,
a central fluid-filled cavity and a small gathering of cells at one end known
as the inner cell mass. Developmental studies show that the cells of the
outer wall become the trophoblast (feeding layer) and are precursors to the
later placenta. Ultimately, all these cells are discarded at birth. (emphasis
The clear implication is that there is absolutely no relationship or interaction
between these two cell layers, and so the "entity" is not a "developmental
individual" yet. However, quoting Larsen:
These centrally place blastomeres are now called the inner cell mass, while
the blastomeres at the periphery constitute the outer cell mass. Some exchange
occurs between these groups. ... The cells of this germ disc (the inner cell
layer) develop into the embryo proper and also contribute to some of the
extraembryonic membranes. (emphasis added)
Similarly, it is not factually correct to state that all of the cells from
the outer trophoblast layer are discarded after birth. Quoting Moore:
The chorion, the amnion, the yolk sac, and the allantois constitute the fetal
membranes. They develop from the zygote but do not participate in the formation
of the embryo or fetus - except for parts of the yolk sac and allantois.
Part of the yolk sac is incorporated into the embryo as the primordium of
the gut. The allantois forms a fibrous cord that is known as the urachus
in the fetus and the median umbilical ligament in the adult. It extends from
the apex of the urinary bladder to the umbilicus. (emphasis added)
Since scientists, in trying to "reach" young students in a more familiar
language, sometimes use popularized (but scientifically inaccurate and
misleading) terms themselves, the ever-vigilant O'Rahilly expresses concern
in his classic text about the use of the term "fetal membranes":
The developmental adnexa, commonly but inaccurately referred to as the "fetal
membranes," include the trophoblast, amnion, chorion, umbilical vesicle (yolk
sac), allantoic diverticulum, placenta and umbilical cord. They are genetically
a part of the individual and are composed of the same germ layers. (emphasis
Consequently, it is also scientifically incorrect to claim that only the
inner cell layer constitutes the "embryo proper." The entire blastocyst -
including both the inner and the outer cell layers - is the human embryo,
the human being.
Finally, McCormick claims that this "pre-embryo" has not yet decided how
many individuals it will become, since the cells are totipotent and twinning
can still take place. Therefore, they argued, there is no "individual" present
until 14-days and the formation of the primitive streak, after which twinning
cannot take place.
However, twinning is possible after 14 days, e.g., with fetus-in-fetu and
Siamese twins. Quoting from O'Rahilly again:
Partial duplication at an early stage and attempted duplication from 2 weeks
onward (when bilaterial symmetry has become manifest) would result in conjoined
twins (e.g., "Siamese twins"). (emphasis added)
And even Karen Dawson acknowledges this as scientific fact in her article
in Embryo Experimentation:
After the time of primitive streak formation, other events are possible which
indicate that the notion of "irreversible individuality" may need some review
if it is to be considered as an important criterion in human life coming
to be the individual human being it is ever thereafter to be. There are two
conditions which raise questions about the adequacy of this notion: conjoined
twins, sometimes known as Siamese twins, and fetus-in-fetu. ... Conjoined
twins arise from the twinning process occurring after the primitive streak
has begun to form, that is, beyond 14 days after fertilization, or, in terms
of the argument from segmentation, beyond the time at which irreversible
individuality is said to exist. ... This situation weakens the possibility
of seeing individuality as something irreversibly resolved by about 14 days
after fertilization. This in turn raises questions about the adequacy of
using the landmark of segmentation in development as the determinant of moral
status. (emphasis added)
It is unfortunate that the NIH Human Embryo Research Panel did not read this
particular portion of the Singer et al book before making their recommendations
about the moral status of the early human embryo.
The scientific fact is that there is no such thing as a "pre-embryo" in the
real world. The term is a complete myth. It was fabricated out of thin air
in order to justify a number of things that ordinarily would not be justifiable.
Quoting O'Rahilly, who sits on the international board of Nomina Embryologica,
The ill-defined and inaccurate term "pre-embryo," which includes the embryonic
disk, is said either to end with the appearance of the primitive streak or
to include neurulation. The term is not used in this book. (emphasis added)
Unfortunately, the convenient but mythological term "pre-embryo" will be
used to "scientifically" justify several of the other "scientific myths"
to follow, which in turn will justify public policy on abortion and human
embryo research world-wide.
MYTH 8: "Pregnancy begins with the implantation of the blastocyst (i.e.,
about 5-7 days)."
FACT 8: This definition of "pregnancy" was initiated to accommodate the
introduction of the process of in vitro fertilization, where fertilization
takes place artificially outside the mother in a petri dish, and then the
embryo is artificially introduced into the woman's uterus so that implantation
of the embryo can take place. Obviously, if the embryo is not within the
woman's body, she is not "pregnant" in the literal, traditional sense of
the term. However, this artificial situation cannot validly be substituted
back to redefine "normal pregnancy," in which fertilization does takes place
within the woman's body in her fallopian tube, and subsequently the embryo
itself moves along the tube to implant itself into her uterus. In normal
situations, pregnancy begins at fertilization, not at implantation. Quoting
Human pregnancy begins with the fusion of an egg and a sperm, but a great
deal of preparation precedes this event. First both male and female sex cells
must pass through a long series of changes (gametogenesis) that converts
them genetically and phenotypically into mature gametes, which are capable
of participating in the process of fertilization. Next, the gametes must
be released from the gonads and make their way to the upper part of the uterine
tube, where fertilization normally takes place. Finally, the fertilized egg,
now properly called an embryo, must make its way into the uterus, where it
sinks into the uterine lining (implantation) to be nourished by the mother.
MYTH 9: "The 'morning-after pill', RU-486, and the IUD are not abortifacient;
they are only methods of contraception."
FACT 9: The "morning-after pill," RU-486, and the IUD can be abortifacient,
if fertilization has taken place. Then they would act to prevent the implantation
of an already existing human embryo - the blastocyst - which is an existing
human being. If the developing human blastocyst is prevented from implanting
into the uterus, then obviously the embryo dies. In effect, these chemical
and mechanical methods of contraception have become methods of abortion as
well. Quoting Moore:
The administration of relatively large doses of estrogens ("morning-after
pill") for several days, beginning shortly after unprotected sexual intercourse,
usually does not prevent fertilization but often prevents implantation of
the blastocyst. Diethylstilbestrol, given daily in high dosage for 5-6 days,
may also accelerate passage of the dividing zygote along the uterine tube
... Normally, the endometrium progresses to the secretory phase of the menstrual
cycle as the zygote forms, undergoes cleavage, and enters the uterus. The
large amount of estrogen disturbs the normal balance between estrogen and
progesterone that is necessary for preparation of the endometrium for
implantation of the blastocyst. Postconception administration of hormones
to prevent implantation of the blastocyst is sometimes used in cases of sexual
assault or leakage of a condom, but this treatment is contraindicated for
routine contraceptive use. The "abortion pill" RU-486 also destroys the conceptus
by interrupting implantation because of interference with the hormonal
environment of the implanting embryo. ... An intrauterine device (IUD) inserted
into the uterus through the vagina and cervix usually interferes with
implantation by causing a local inflammatory reaction. Some IUDs contain
progesterone that is slowly released and interferes with the development
of the endometrium so that implantation does not usually occur. (emphasis
And since the whole human blastocyst is the embryonic human being - not just
the inner cell layer - the use of chemical abortifacients that act "only"
on the outer trophoblast layer of the blastocyst, e.g., methotrexate, would
be abortifacient as well.
MYTH 10: "Human embryo research, human cloning, stem cell research, and the
formation of chimeras are acceptable kinds of research because until implantation
or 14 days there is only a 'pre-embryo', a 'potential' human embryo or human
being present. A real human embryo and a human being (child) do not actually
begin unless and until the 'pre-embryo' is implanted into the mother's uterus."
FACT 10: These claims are currently being made by bioethicists, research
scientists, pharmaceutical companies and other biotech research companies
- even by some members of Congress. However, they too are "scientific myths."
Scientifically it is perfectly clear that there is no such thing as a
"pre-embryo," as demonstrated in Fact 7. As demonstrated in the background
material, the immediate product of fertilization is a human being, a human
embryo, a human child - the zygote. This zygote is a newly existing, genetically
unique, genetically male or female, individual human being - it is not a
"potential" or a "possible" human being. And this developing human being
is a human being, a human embryo, a human child whether or not it is implanted
artificially into the womb of the mother.
Fertilization and cloning are different processes, but the immediate products
of these processes are the same. The immediate product of cloning is also
a human being - just as in fertilization. It is not a "pre-embryo" or a
"potential" human embryo or human being. Stem cell research obtains its "stem
cells" by essentially exploding or otherwise destroying and killing a newly
existing human blastocyst who is, scientifically, an existing human being.
The formation of chimeras, i.e., the fertilization of a gamete of one species
(e.g., a human ovum) with the gamete of another species (e.g., a monkey sperm)
also results in an embryo which is "half-human." All of these types of research
have been banned by most countries in the world. And all of these types of
research are essentially human embryo research - banned in the United States
by Congress if federal funds are used.
MYTH 11: "Certain early stages of the developing human embryo and fetus,
e.g., during the formation of ancestral fish gills or tails, demonstrates
that it is not yet a human being, but is only in the process of becoming
one. It is simply "recapitulating" the historical evolution of all of the
FACT 11: This "scientific myth" is yet another version of the "potential,"
"possible," "pre-embryo" myths. It is an attempt to deny the early human
embryo its real identity as a human being and its real existence. But quoting
once again from O'Rahilly:
The theory that successive stages of individual development (ontogeny) correspond
with ("recapitulate") successive adult ancestors in the line of evolutionary
descent (phylogeny) became popular in the 19th century as the so-called
biogenetic law. This theory of recapitulation, however, has had a "regrettable
influence in the progress of embryology" (citing de Beer). ... Furthermore,
during its development an animal departs more and more from the form of other
animals. Indeed, the early stages in the development of an animal are not
like the adult stages of other forms, but resemble only the early stages
of those animals.
Hence, the developing human embryo or fetus is not a fish or a frog,
but is categorically a human being - as has been already demonstrated.
MYTH 12: "Maybe a human being begins at fertilization, but a human person
does not begin until after 14-days, when twinning cannot take place."
FACT 12: The question as to when a human person begins is a philosophical
question - not a scientific question. I will not go into great detail here,
but since many of the current popular "personhood" claims in bioethics are
also based on mythological science, it would be useful to just look very
briefly at these philosophical (or sometimes, theological) arguments for
scientific accuracy as well.
Philosophically, virtually any claim for so-called "delayed personhood" involves
the theoretical disaster of accepting that the idea or concept of a mind/body
split has any correlate or reflects the real world. Historically this problem
was simply the consequence of wrong-headed thinking about reality, and was/is
totally indefensible. It was abandoned with great embarrassment after Plato
(even by Plato himself in his Parmenides!), but unfortunately resurfaces
from time to time, e.g., as with Descartes in his Meditations, and now again
with contemporary bioethics. And as in the question of when a human being
begins, if the science used to ground these philosophical "personhood" arguments
is incorrect, the conclusions of those arguments (which are based on that
science) are also incorrect and invalid.
The particular argument in Myth 12 is also made by McCormick and Grobstein
(and their numerous followers). It is based on their biological claim that
the "pre-embryo" is not a developmental individual, and therefore not a person,
until after 14 days when twinning can no longer take place. However, it has
already been scientifically demonstrated here that there is no such thing
as a "pre-embryo," and that in fact the embryo begins as a "developmental
individual" at fertilization. Furthermore, twinning can take place after
14 days. Thus, simply on the level of science, the philosophical claim of
"personhood" advanced by these bioethicists is invalid and indefensible.
MYTH 13: "A human person begins with 'brain birth', the formation of the
primitive nerve net, or the formation of the cortex - all physiological
structures necessary to support thinking and feeling."
FACT 13: Such claims are all pure mental speculation, the product of imposing
philosophical (or theological) concepts on the scientific data, and have
no scientific evidence to back them up. As the well-known neurological researcher
D. Gareth Jones has succinctly put it, the parallelism between brain death
and brain birth is scientifically invalid. Brain death is the gradual or
rapid cessation of the functions of a brain. Brain birth is the very gradual
acquisition of the functions of a developing neural system. This developing
neural system is not a brain. He questions, in fact, the entire assumption
and asks what neurological reasons there might be for concluding that an
incapacity for consciousness becomes a capacity for consciousness once this
point is passed. Jones continues that the alleged symmetry is not as strong
as is sometimes assumed, and that it has yet to provided with a firm biological
MYTH 14: "A 'person' is defined in terms of the active exercising of 'rational
attributes' (e.g., thinking, willing, choosing, self-consciousness, relating
to the world around one, etc.), and/or the active exercising of 'sentience'
(e.g., the feeling of pain and pleasure)."
FACT 14: Again, these are philosophical terms or concepts, which have been
illegitimately imposed on the scientific data. The scientific fact is that
the brain, which is supposed to be the physiological support for both "rational
attributes" and "sentience," is not actually completely developed until young
adulthood. Quoting Moore:
Although it is customary to divide human development into prenatal (before
birth) and postnatal (after birth) periods, birth is merely a dramatic event
during development resulting in a change in environment. Development does
not stop at birth. Important changes, in addition to growth, occur after
birth (e.g., development of teeth and female breasts). The brain triples
in weight between birth and 16 years; most developmental changes are completed
by the age of 25. (emphasis added)
One should also consider simply the logical - and very real - consequences
if a "person" is defined only in terms of the actual exercising of "rational
attributes" or of "sentience." What would this mean for the following list
of adult human beings with diminished "rational attributes": the mentally
ill, the mentally retarded, the depressed elderly, Alzheimer's and Parkinson's
patients, drug addicts, alcoholics - and for those with diminished "sentience,"
e.g., the comatose, patients in a "vegetative state," paraplegics and other
paralyzed and disabled patients, diabetics or other patients with nerve or
brain damage, etc.? Would they then be considered as only human beings but
not also as human persons? Would that mean that they would not have the same
ethical rights and protections as those adult human beings who are considered
as persons? Is there really such a "split" between a human being and a human
In fact, this is the position of bioethics writers such as the Australian
animal rights philosopher Peter Singer, the recently appointed Director of
the Center for Human Values at Princeton University. Singer argues that the
higher primates, e.g., dogs, pigs, apes, monkeys, are persons - but that
some human beings, e.g., even normal human infants, and disabled human adults,
are not persons. Fellow bioethicist Norman Fost actually considers "cognitively
impaired" adult human beings as "brain dead." Philosopher/bioethicist R.G.
Frey has also published that many of the adult human beings on the above
list are not "persons," and suggests that they be substituted for the higher
primates who are "persons" in purely destructive experimental research. The
list goes on.
Ideas do have concrete consequences - not only in one's personal life, but
also in the formulation of public policies. And once a definition is accepted
in one public policy, the logical extensions of it can then be applied,
invalidly, in many other policies, even if they are not dealing with the
same exact issue - as happens frequently in bioethics. Thus, the definitions
of "human being" and of "person" which have been concretized in the abortion
debates have been transferred to several other areas, e.g., human embryo
research, cloning, stem cell research, the formation of chimeras, the use
of abortifacients - even the issues of brain death, brain birth, organ
transplantation, the removal of food and hydration, and research with the
mentally ill or the disabled. But both private choices and public policies
should incorporate sound and accurate science whenever possible. What I have
tried to indicate is that in these current discussions, individual choices
and public policies have been based on "scientific myth," rather than on
objective scientific facts.