In 1991, when he was just thirty years old, actor Michael J. Fox was diagnosed with Parkinson’s disease. While Parkinson’s normally afflicts adults over the age of sixty (roughly the disease strikes about 1% of that age group), as Michael J. Fox’s case indicates, younger people can develop Parkinson’s as well. We do not yet fully understand Parkinson’s disease, but we do know that with Parkinson’s, the patient’s brain cells (or neurons) die off. The neurons affected by Parkinson’s control motor function and mood. Persons with advanced Parkinson’s have trouble moving and speaking, and their hands and legs may tremble, twitch, or freeze up. They may also experience mood swings and depression. In the very late stages of the disease, they can also lose mental function. Currently, no cure exists for Parkinson’s disease. Scientists hope, however, that at some point in the future, embryonic stem cells might be used to treat Parkinson’s disease. What are stem cells, and how might stem cell therapies help? A stem cell is a very special kind of cell. Stem cells start out as general purpose cells, which can then “specialize” themselves to carry out the role of other kinds of cells, such as blood cells, muscle cells, or even brain cells. The function of a stem cell, therefore, is to serve as a kind of “spare part” in the repair system of the human body. This has suggested to researchers the idea that stem cells could be transplanted from one body to another for therapeutic use. Stem cell transplants are already done today. The best known example is a bone marrow transplant for leukemia patients – bone marrow contains blood stem cells that can take over the role of the diseased blood cells in a person with leukemia. This type of stem cell transplant uses what are called “adult stem cells.” Adult stem cells have already specialized to perform a particular function (e.g., the function of a blood cell), and recent research indicates great promise in their use. Stem cells can be collected from another adult, an infant, or a fetus. Researchers have also focused on experimenting with embryonic stem cells, however. As the name suggests, embryonic stem cells are extracted from a one-week-old human blastocyst (which at this point consists of fifty to one hundred cells). The advantage of embryonic stem cells is that they are not yet specialized – they have not yet adapted to any particular function. So in principle, an embryonic stem cell could be genetically manipulated to turn into whatever type of stem cell is needed for therapy, whereas adult stem cells cannot. The process of making this happen, however, is still in its infancy. The embryonic stem cells used in experiments today are obtained from embryos donated by couples that have undergone in vitro fertilization (IVF), a technique used to help infertile couples have children. IVF involves the creation of fertilized eggs outside of the womb, a process that often results in more fertilized eggs than are tr.

1. In 1991, when he was just thirty years old, actor Michael J. Fox
was diagnosed with Parkinson’s disease. While Parkinson’s
normally afflicts adults over the age of sixty (roughly the
disease strikes about 1% of that age group), as Michael J. Fox’s
case indicates, younger people can develop Parkinson’s as well.
We do not yet fully understand Parkinson’s disease, but we do
know that with Parkinson’s, the patient’s brain cells (or
neurons) die off. The neurons affected by Parkinson’s control
motor function and mood. Persons with advanced Parkinson’s
have trouble moving and speaking, and their hands and legs may
tremble, twitch, or freeze up. They may also experience mood
swings and depression. In the very late stages of the disease,
they can also lose mental function.
Currently, no cure exists for Parkinson’s disease. Scientists
hope, however, that at some point in the future, embryonic stem
cells might be used to treat Parkinson’s disease. What are stem
cells, and how might stem cell therapies help?
A stem cell is a very special kind of cell. Stem cells start out as
general purpose cells, which can then “specialize” themselves to
carry out the role of other kinds of cells, such as blood cells,
muscle cells, or even brain cells. The function of a stem cell,
therefore, is to serve as a kind of “spare part” in the repair
system of the human body. This has suggested to researchers the
idea that stem cells could be transplanted from one body to
another for therapeutic use.
Stem cell transplants are already done today. The best known
example is a bone marrow transplant for leukemia patients –
bone marrow contains blood stem cells that can take over the
role of the diseased blood cells in a person with leukemia. This
type of stem cell transplant uses what are called “adult stem
cells.” Adult stem cells have already specialized to perform a
particular function (e.g., the function of a blood cell), and
recent research indicates great promise in their use. Stem cells
can be collected from another adult, an infant, or a fetus.

2. Researchers have also focused on experimenting with embryonic
stem cells, however. As the name suggests, embryonic stem
cells are extracted from a one-week-old human blastocyst
(which at this point consists of fifty to one hundred cells). The
advantage of embryonic stem cells is that they are not yet
specialized – they have not yet adapted to any particular
function. So in principle, an embryonic stem cell could be
genetically manipulated to turn into whatever type of stem cell
is needed for therapy, whereas adult stem cells cannot. The
process of making this happen, however, is still in its infancy.
The embryonic stem cells used in experiments today are
obtained from embryos donated by couples that have undergone
in vitro fertilization (IVF), a technique used to help infertile
couples have children. IVF involves the creation of fertilized
eggs outside of the womb, a process that often results in more
fertilized eggs than are transplanted into the uterus (the extra
fertilized eggs are created on purpose, because not all the eggs
resulting from this process turn out to be viable). In the process
of obtaining stem cells, the embryo is destroyed. (Normally,
most of the unused embryos resulting from IVF are discarded,
although sometimes they are frozen for possible future use).
No embryonic stem cell therapies have yet been developed.
Regarding Parkinson’s disease, however, the hope is that
embryonic stem cells could eventually be used to replace the
neurons Parkinson’s has killed off with neuron stem cells via a
transplant. These stem cells would then specialize to take over
the function of the cells that have died. So far, research on rats
and monkeys has been promising.
What does all of this have to do with ethics? On one hand,
embryonic stem cell researchers hold out hope for using stem
cells to cure or at least to alleviate some symptoms of
Parkinson’s as well as other serious diseases (stem cells might
also be used to help accident victims with brain injuries, spinal
cord injuries, and patients with Alzheimer’s). On the other
hand, every time a new stem cell line is started, a human
embryo is destroyed. Clearly, if any research, no matter how

3. useful, resulted in the death of another human adult or child,
such research would be unethical. Yet researchers often
maintain that this is not a fair comparison to the destruction of
an embryo. Why? Because these embryos only consist of fifty to
one hundred human cells. This blastocyst is not able to feel
pain, nor is it conscious; in fact, it would probably be discarded
anyway.
Of course, opponents of embryonic stem cell research do not
like the idea of discarding embryos either. This is because they
view embryos as having intrinsic worth (and thus, rights as
well). This is the heart of the issue: what is the moral status of a
human embryo? Although we might talk disparagingly of “just
some cells,” those cells are human; even more importantly,
those cells – unlike a culture of skin cells, say – have the
capability of developing into a child and would do so under
natural conditions.