On the occasion of its 12th General Assembly, the Pontifical Academy
for Life celebrated an international Congress on the theme: "The human
embryo in the pre-implantation phase: Scientific aspects and bioethical
considerations". At the conclusion of the Congress, the Academy offered
to the Ecclesial Community and to the general public, certain
considerations on the theme of its reflection.
1. It can escape no one that the contemporary bioethical debate,
especially in recent years, has focused mainly on the reality of the
human embryo, considered in itself or in relation to how other human
beings behave towards it. This is only natural since the multiple
implications (scientific, philosophical, ethical, religious,
legislative, financial, ideological, etc.) connected to these areas
inevitably catalyze different interests, as well as attract the
attention of those in search of authentic ethical action.
The need to ask the basic question: "Who or what is the human
embryo", has therefore become unavoidable, in order to draw from a
relevant, consistent answer to it criteria for action that fully respect
the integral truth of the embryo itself.
To this end, in accordance with a correct bioethical methodology, it
is necessary first of all to look at the data that the most up-to-date
knowledge puts at our disposal today, enabling us to know in great
detail about the different processes through which a new human being
begins its existence. These data must then be subjected to an
anthropological interpretation in order to highlight their significance
and the emerging values to which to refer in the last place, to derive
the moral norms for practical action and standard procedures.
Human life begins at conception
2. Consequently, in light of the most recent discoveries of
embryology, it is possible to establish certain universally recognized
a) The moment the sperm penetrates the oocyte is when the existence
of a new "human being" begins. Fertilization induces a whole series of
consecutive events and transforms the egg cell into a "zygote". In the
human species, the nucleus of the spermatozoid (contained in the head)
and a centriole (which will play a determining role in the formation of
the mitotic fusus in the act of the first cellular division) enter the
oocyte; the plasmatic membrane remains on the outside. The male nucleus
undergoes profound biochemical and structural changes that depend on the
ovular cytoplasm in preparation for the role that the male genome will
immediately begin to play. Here we are witnessing the decondensation of
the chromatin (induced by factors synthesized in the final phases of
ovogenesis) that makes transcription of the paternal genes possible.
After the sperm penetrates the oocyte, it completes its second
meiotic division and expels the second polar body, reducing its genome
to a haploid number of chromosomes in order to associate with the
chromosomes brought by the male nucleus the karyotype characteristic of
the species. At the same time, it encounters an "activation" from the
metabolic viewpoint, with a view to the first mitosis.
It is always the cytoplasmatic environment of the oocyte that induces
the centriole of the spermatozoon to duplicate itself, thereby
constituting the centrosome of the zygote. This centrosome duplicates
itself with a view to constituting the microtubule that will make up the
The two sets of chromosomes find the mitotic fusus already formed and
arrange themselves at the equator in a position of metaphase. The other
phases of mitosis follow, and finally the cytoplasm divides and the
zygote gives life to the first two blastomeres.
The activation of the embryonic genome is probably a gradual process.
In the single-cell human embryo seven genes are already active; others
are expressed during the passage from the zygote stage to that of two
b) Biology, and more particularly embryology, provides the
documentation of a definite direction of development, this means that
the process is "oriented"
to the direction of a progressive differentiation and acquisition of
complexity and cannot regress from the stages it has already completed.
c) A further point acquired with the earliest phases of development
is the "autonomy" of the new being in the process of the
auto-duplication of genetic material.
d) The characteristics of "gradualness" (the time needed for the
passage from a less differentiated stage to a more differentiated stage)
and of the "coordination" of development (the existence of mechanisms
that regulate the developmental process in a unitary whole) are also
strictly linked to the property of "continuity".
virtually ignored at the beginning of the bioethical debate
are considered more and more important in recent times because of the
successive discoveries that research offers on the dynamic of embryonic
development also at the "morula" stage, which precedes the formation of
All together, these trends already form the basis for interpreting
the zygote as being a primordial "organism" (monocellular organism) that
consistently expresses its potentials for development through a
continuous integration, first, among the various internal components and
then, among the cells to which it progressively gives rise. Their
integration is both morphological and biochemical. The research that has
been underway for several years now only yields further "proofs" of this
3. These breakthroughs of modern embryology must be submitted to the
scrutiny of philosophical and anthropological interpretation in order to
understand the precious value inherent in and expressed by every human
being, also at the embryonic stage. Thus, the basic question of the
moral status of the embryo must be faced squarely.
It is well-known that, among the different hermeneutical proposals
present in the current bioethical debate, various moments in the
embryonic development of the human being have been indicated to which a
moral status can be attributed to the embryo, and claims are put forward
based on "extrinsic" criteria (that is, starting with factors external
to the embryo itself).
However, this approach has not proved suitable for truly identifying
the moral status of the embryo, since any possible judgment ends by
being based on factors that are wholly conventional and arbitrary.
To be able to formulate a more objective opinion on the reality of
the human embryo and therefore to deduce ethical indications from it, it
is necessary instead to take into consideration criteria that are
"intrinsic" to the embryo itself, starting precisely with the data that
scientific knowledge puts at our disposal.
Is the embryo already a person?
It can be concluded from this data that the human embryo in the phase
of pre-implantation is already: a) a being of the human species; b) an
individual being; c) a being that possesses in itself the finality to
develop as a human person together with the intrinsic capacity to
achieve such development.
From all this may one conclude that the human embryo in the
pre-implantation stage is really already a "person"? It is obvious that
since this is a philosophical interpretation, the answer to this
question cannot be of a "definite kind", but must remain open, in any
case, to further considerations.
Yet, on the precise basis of the available biological data, we
maintain that there is no significant reason to deny that the embryo is
already a person in this phase.
Of course, this presupposes an interpretation of the concept of the
person of a substantial type, referring, that is, to human nature itself
as such, rich in potential that will be expressed during the embryo's
development and also after birth. To support this position, it should be
noted that the theory of immediate animation, applied to every human
being who comes into existence, is shown to be fully consistent with his
biological reality (in addition to being in "substantial" continuity
with the thought of Tradition).
The Psalm states: "For you did form my inward parts, you did knit me
together in my mother's womb. I praise you, for you are fearful and
wonderful. Wonderful are your works! You know me right well" (Ps
139:13-14), referring to God's direct intervention in the creation
of every new human being's soul.
From the moral viewpoint, moreover, over and above any consideration
of the human embryo's personality, the mere fact of being in the
presence of a human being (and even the doubt of this would suffice)
would demand full respect for the embryo's integrity and dignity: any
conduct that might in some way constitute a threat or an offence to its
fundamental rights, and first and foremost the right to life, must be
considered as seriously immoral.
To conclude, we would like to make our own the words that the Holy
Father Benedict XVI spoke in his Address to our Congress: "God's love
does not differentiate between the newly conceived infant still in his
or her mother's womb and the child or young person, or the adult and the
elderly person. God does not distinguish between them because he sees an
impression of his own image and likeness (Gn 1:26) in each one.
"He makes no distinctions because he perceives in all of them a
reflection of the face of his Only-begotten Son, whom 'he chose...
before the foundation of the world.... He predestined us in love to be
his sons... according to the purpose of his will' (Eph 1:4-6)" (Address,
27 February 2006; L'Osservatore Romano English edition, 8 March,