A microphotograph of human embryonic
stem cells taken at a Brazilian laboratory.
Human embryo:
A microphotograph of a human embryo consisting
of seven undifferentiated stem cells in the process of having one stem cell removed
for pre-implantation genetic diagnosis.
A consensus exists that that such embryos are alive. They contain human
DNA and are thus human life.
The controversy over embryonic stem cell research centers on whether human
life in the form of an embryo less than two weeks after conception is also a human person.
If it is a person, then extracting stem cells constitutes first degree
murder.
If it is not a person, then removing stem cells is morally acceptable.
Overview:
Stem cells are seen by many researchers as having virtually unlimited
application in the treatment and cure of many human diseases and disorders
including Alzheimer's, diabetes, cancer, strokes, etc. Stem cells come in three general
types:
Embryonic stem cells are a primitive type of cell that can be coaxed into developing
into all of the 220 types of cells found in the human body (e.g. blood cells,
heart cells, brain cells, nerve cells, etc). In the past, they have always been derived from human embryos
in a process that causes the death of the embryos. However, new research is
developing techniques to convert skin cells into Induced Pluripotent Stem
Cells (iPS cells) that emulate embryonic
stem cells.
Adult stem cells bear some similarities to embryonic stem cells.
Research using adult cells has a two decade head start on embryonic stem
cells. Thus, potential treatments have already advanced to human trial
stage. Unfortunately, adult cells are limited in flexibility, and are only
capable of developing into a few of the cell types.
Induced pluripotent stem cells are specially treated ordinary cells
-- e.g. skin cells -- that are specially processed to exhibit some of the
properties of embryonic stem cells. Research in this area is just beginning.
However the process seems to offer the advantages of embryonic stem cells
without the ethical and rejection problems.
Many pro-lifers believe that human life, in the form of an ovum and
spermatozoon, becomes a human person at the time of fertilization. They
view the killing
of any embryo in order to extract its stem cells to be a form of homicide. They are
generally opposed to such research. Others disagree. They believe that an embryo
has the potential to develop into a person, but is not a person itself. They
note that an embryo is not sentient; it has no brain, sensory organs, ability to
think, memory, awareness of its surroundings, consciousness, internal organs, arms,
legs, head, etc. They feel that research using stem cells derived from embryos
is ethical. Fortunately, if iPS cell technology develops as expected, it will
eventually replace the need to derive stem cells from embryos.