President Bush’s recently appointed Council on Bioethics has begun
to deliberate about human reproductive cloning and embryo stem cell
research just as the US National Academy of Sciences has released its
panel of experts’ report on these subjects. The Academy’s panel opposes
reproductive cloning, that is, the production of babies who would be
genetic copies of other people, and recommends that it be outlawed. It,
however, endorses cloning embryos as tools for research into treating
disease (therapeutic cloning). Judging from the composition of the
President’s Bioethics Council and its initial public statements, that body
is likely to end up opposing both types of cloning. I would guess that it
is also likely to endorse President Bush’s decision of August 9, 2001 to
forbid the further production of embryos for research and to thus limit
the number of useable lines of embryo stem cells to those in existence on
that date. Meanwhile, Congress is resuming its own debate on legislation
regarding these matters, on hold since September.
Lost in most of
these discussions, which tend to focus on matters of human dignity and the
status of the embryo, is the fact that to produce human embryos outside a
woman’s body requires not just human sperm, which apparently has been
readily accessible since biblical times and, no doubt, long before.
Producing embryos also requires human eggs, and getting at those is much
more difficult. Granted, in vitro fertilization (IVF), which requires
eggs, has become a standard part of reproductive medicine, but it requires
relatively few eggs. Furthermore, these eggs are usually extracted from
women willing to take risks to produce their own biological children. Even
so, questions have been raised about possible negative consequences of IVF
for women’s health.
Manipulating a woman’s physiology to make her
produce large numbers of eggs for research, while encouraging her to do so
by paying for them, raises questions of medical and scientific
exploitation and ethics that have hardly been discussed. To stimulate a
woman’s ovaries to release more than the usual single monthly egg she must
receive hormones, first to suppress ovulation entirely and then to
hyperstimulate it. The ripened eggs are then extracted surgically from the
ovaries while inspecting them by ultrasound. None of this is fun and there
is, as yet, no way to know about its safety. To date, we know that
hyperstimulation can shut down a woman’s ovaries so that she experiences
premature menopause with incumbent increased risks of osteoporosis and
other symptoms of early aging. Some observations also suggest that the
hormones may increase the incidence of ovarian and, perhaps, breast
cancer, but there are not enough data to be sure.
Meanwhile, it is
by no means clear that the therapeutic opportunities to be derived from
embryo stem cells are superior to those of using stem cells isolated from
the tissues of adults or from umbilical cord blood. As we go to press, a
University of Minnesota scientist announced that she has discovered a new,
versatile class of adult stem cells she calls “multipotent adult
progenitor cells” that can grow into several types of body tissue. The
rush to explore the potential of embryo stem cells appears to be based on
the pursuit of patents and near-term profits. There are more acceptable
alternatives likely to yield therapies and cures.
Ruth Hubbard
is a CRG Board Member and a Professor Emerita at Harvard
University.