Do the Math: Experimental Cloning Exploits Women

Date: 07/02/2002

Early this year, the National Academy of Sciences (NAS) announced:

“Because many eggs are needed for human reproductive cloning attempts, human experimentation could subject more women to adverse health effects – either from high levels of hormones used to stimulate egg production or because more women overall would be sought to donate eggs, which involves surgery with its own inherent risks.”

— “U.S. Policy-makers Should Ban Human Reproductive Cloning,” Press Release, The National Academies, announcing the publication of Scientific and Medical Aspects of Human Reproductive Cloning.

What the Academy did NOT say, however, is that this objection to “reproductive” cloning applies even more strongly to the type of cloning the panel recommends go forward — cloning to produce human embryos for tissue harvesting and other destructive research.

In fact, both the “reproductive” or live birth cloning the NAS panel would ban, and the human experimental cloning the panel recommends go forward, use exactly the same technique to create the clone, and the resulting embryos are indistinguishable. The process, as well as the product, is identical.

That process is called Somatic Cell Nuclear Transfer (SCNT, now also being called by a variety of names such as “nuclear cell transfer,” “nuclear transplantation,” etc.) In SCNT, the nucleus is removed from the donated egg, and replaced with a nucleus taken from a body cell of the subject being cloned. The modified egg is then stimulated and the new, cloned embryo begins to develop.

The NAS Panel recommended the production of cloned human embryos to produce genetically matched embryonic stem cells for each patient. But given the large pool of potential patients, numbering in the tens of millions, the demand for eggs would almost certainly be far higher for this experimental cloning — advocated by the NAS panel — than for live birth cloning.

NOW CONSIDER SOME NUMBERS:

Potential U.S. Patient Populations for Stem Cell-Based Therapies (according to the National Academy of Sciences)1

 

Condition

Number of Patients

Cardiovascular disease 58 million
Autoimmune diseases 30 million
Diabetes 16 million
Osteoporosis 10 million
Cancers 8.2 million
Alzheimer’s disease 5.5 million
Parkinson’s disease 5.5 million
Burns (severe) 0.3 million
Spinal-cord injuries 0.25 million
Birth Defects 0.15 million

These numbers give a total patient population of 133.9 million. But as the NAS notes, these conditions “occur in many forms and thus not every person with these diseases could potentially benefit from stem cell therapies.” Conservatively, let us say that perhaps 10% of the total will be eligible for such therapies, or 13.4 million.

Now, given the inefficiencies associated with cloning, consider the estimated number of oocytes (eggs) and donors that would be needed to treat disease as envisaged by cloning proponents:

Assume 20% cloning efficiency.2

Assume 10% efficiency at initiating an embryonic stem (ES) cell culture (from stem cells harvested from the cloned embryo).3

Assume that one could collect 10 eggs per donor.4 researchers hoped to collect about two dozen eggs a month from donors, but even that was an ambitious goal, and when the eggs did arrive there were often only five or 10 to work with,” Joannie Fischer, “The First Clone,” U.S. News and World Report, 12/3/01.]

IN ORDER TO PROVIDE GENETICALLY MATCHED EMBRYONIC STEM CELLS DERIVED FROM CLONING TO TREAT THE POTENTIAL PATIENT POOL, SCIENTISTS WOULD HAVE TO OBTAIN AT LEAST 670 MILLION EGGS, DONATED BY AT LEAST 67 MILLION WOMEN.

WHERE WILL ALL THESE EGGS COME FROM?

On its face, these numbers render cloning absurd as a practical avenue for treating disease. Even in the initial research stages, the demand for eggs created by experimental cloning will turn them into a highly sought-after research commodity and create a thriving market for the eggs. This will almost certainly create enormous pressure on poorer women to sell their eggs. Moreover, the process of donating eggs involves, as the NAS recognizes, health risks for women, including massive injections of hormones to produce ovarian hyperstimulation, with possible loss of the ovary, rupture and sepsis in the abdominal cavity, and a possible increased risk of ovarian cancer.

Do the Math: Cloning humans – whether with the intent to produce a live birth or treat disease – is impractical, inefficient and will almost certainly prove exploitative of women.

  1. Stem Cells and the Future of Regenerative Medicine, National Research Council/Institute of Medicine, The National Academy of Sciences, available online at: books.nap.edu/html/stem_cells/reportbrief.pdf
  2. This is based on published reports of animal clones reaching the blastocyst stage (the stage at which stem cells develop) and NOT live birth. For example, 20 to 30 percent of cattle cloned by Advanced Cell Technology (ACT, the company which in November announced cloning the first human embryos) reach the blastocyst stage. With other species the range has been < 10 % up to 39%. Using both parthenogenesis and somatic cell nuclear transfer, ACT experienced a 100% failure rate in its 41 attempts to create human cloned embryos that would develop into a source for stem cells. None of the human clones created by SCNT reached the blastocyst stage. None of the embryos created by parthenogenesis could produce embryonic stem cells.
  3. James Thomson, of the University of Wisconsin, used 36 embryos to derive 5 human ES cell lines (13.8%). The Jones Institute used 110 embryos to get three lines (2.7%). When Wakayama et al. cloned mice and harvested ES cells, they had a 3.4% efficiency.
  4. ACT collected 71 eggs from 7 donors – “The [ACT
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