Human Reproductive Cloning and the views of the British Fertility
Society
Dr John Mills, president of the British Fertility Society
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Feb 05
There are two main reasons to consider ‘cloning’ a
human embryo. The first is nuclear transfer for stem cell derivation
(‘therapeutic cloning’), making exact copies of diseased
cells and tissues for experiments that may help us to understand
and treat human disease.
The second is ‘reproductive cloning’, which means
an attempt to create a human as nearly as possible identical to
the original.
The British Fertility Society supports nuclear transfer and stem
cell derivation for the understanding and eventual treatment of
disease. The Society does not support any attempt at reproductive
cloning.
What is cloning?
- Cloning an embryo involves transfer of the nucleus - which
contains the DNA - of any normal cell (except egg or sperm) in
the body, into a human egg (oocyte) from which the original nucleus
has been removed. This cell is then activated (no sperm involved)
to divide. Stem cells are then isolated from the blastocyst (an
early stage of embryo development) a few days later.
- In reproductive cloning this blastocyst would be transferred
to a woman’s uterus in the hope that it would develop into
a child.
Has anyone tried reproductive cloning?
- Reproductive cloning has been used in many animals and the
first successful reproductive cloning experiment produced Dolly,
a sheep.
- We know of no evidence to support claims of pregnancies or
children in humans with this technique.
- Human ‘clones’ do exist in the form of identical
twins but the way in which these clones are derived is quite
different.
Why doesn’t the BFS support human reproductive
cloning?
- We know of no reason to try to clone a human other than curiosity
and believe that any consequences would be disastrous.
- We do know that experiments in many animal species suggest
that there is a significant risk of harm occurring to the cloned
embryo or young.
- Dolly the sheep seemed to age prematurely and developed arthritis
and lung disease before she was put down.
- In most cases of animal cloning work the pregnancies terminate
in miscarriages. Some 90% of fetuses will abort and many of these
will occur late in the pregnancy.
- Many cloned fetuses have shown gross abnormalities of development
and it seems that this is a consequence of an inability to control
their own growth.
- Those young which have survived have a high rate of abnormality
such as failure of organs to develop, increased birth size and
disease of liver and kidney.
- We believe that the likelihood of any development of a normal
cloned fetus is minimal and, in the light of current evidence
from animal research, we feel that any attempt to reproduce a
human clone would be irresponsible.
Further reading
Lorraine Young 2003 Scientific hazards of human reproductive ‘cloning’ Human
Fertility 6, 59-63 Overview: http://www.fertility.org.uk/news/pressrelease/03_08-cloning_warning.html
Human Genome Product Information. Cloning Fact Sheet http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml
Human Cloning: Science Fiction or Reality http://www.bioteach.ubc.ca/Biomedicine/HumanCloning/
The National Academies 2002 Scientific and Medical Aspects
of Human Reproductive Cloning. National Academy Press, Washington
DC
House of Lords 2002
Stem Cell Research – Report http://www.publications.parliament.uk/pa/ld200102/ldselect/ldstem/83/8301.htm