Research Cloning and "Fetus Farming": The Slippery Slope in Action

I. The CurrentSituation

Some scientists and their political allies support human cloning for research purposes (which they call "therapeutic" cloning, although it has not produced any therapies). They say this practice can be kept totally separate from "reproductive" cloning (using cloned human embryos to initiate pregnancies).

However, the cloning procedure is exactly the same in both cases; so many supporters of research cloning admit that allowing it will make reproductive cloning more likely as well.1 It is doubtful that any ban on reproductive use of cloned embryos would be practical, enforceable, or even constitutionally valid once the mass-production of embryos for research purposes is authorized.2

II. "Fetus Farming": An Alarming Development

In recent years this debate has shifted in an alarming direction:
  1. With the support of groups favoring research cloning, many states are considering (and some have passed) laws that allow placing cloned human embryos in women's wombs, but forbid any attempt to let them be born alive. Under these laws, researchers can implant cloned human embryos in wombs, develop them to the fetal stage, then abort them for their cells and tissues (a process some call "fetus farming").
  2. This legislative trend is based on recent scientific evidence suggesting that therapeutic benefits will not be safely obtained from the cloning of human embryos unless such "fetus farming" is allowed.
So the attempt to distinguish therapeutic from reproductive cloning has broken down: What was once called "reproductive" cloning (placing cloned embryos in a womb) is being accepted as a necessary part of so-called "therapeutic" cloning.

This new agenda has required a shift in definitions. Increasingly, "reproductive" cloning is said to occur only if a cloned human being is brought to full term and born alive. In this way a law can be called a ban on "reproductive" cloning even if its only legal effect is to mandate abortion for any woman carrying a cloned unborn child in her womb.

III. Documentation of this Trend

A. The Legislative Slippery Slope to Fetus Farming

Until recently, groups promoting research cloning, such as the Biotechnology Industry Organization (BIO), supported state and federal bills that prohibit implanting a cloned embryo in a womb. For example, in Congress they supported the "Human Cloning Ban and Stem Cell Research Protection Act" of 2003 (S. 303). That bill actually allowed the human cloning procedure, calling it "nuclear transplantation," but banned two things: (1) "implanting or attempting to implant the product of nuclear transplantation into a uterus or the functional equivalent of a uterus"; and (2) maintaining such a cloned human embryo for "more than 14 days from its first cell division," not counting time spent in a freezer.3

BIO told the President's Council on Bioethics in June 2003 that it supported this 14-day limit – adding that this may be reconsidered "umpteen years" from now in light of new facts.4

Yet months before making these remarks to the President's Council, BIO was urging its state affiliates to help pass laws violating this 14-day limit. The national group recommended a new California law on cloning as a "model" for other states.5 That law authorizes "research involving the derivation and use of human embryonic stem cells, human embryonic germ cells, and human adult stem cells from any source, including somatic cell nuclear transplantation."6 California law also bans initiating a pregnancy using a cloned human embryo, but only if that pregnancy "could result in the birth of a human being."7

In fact, the same official who presented BIO's testimony to the President's Council on Bioethics had already testified in support of a New Jersey bill with this same broad language.8 After critics pointed out that the New Jersey bill did not even really ban "reproductive" cloning, the bill's sponsors made its extreme scope even clearer. The final law bans "cloning of a human being," defined as "the replication of a human individual by cultivating a cell with genetic material through the egg, embryo, fetal and newborn stages into a new human individual."9 Developing the cloned embryo to any point short of this to harvest cells and tissues is allowed, and the governor later decided it could be publicly funded. Only letting the cloned human survive "through" this entire process is prohibited.

In keeping with BIO's new approach, at least nine states considered sweeping "therapeutic cloning" bills in 2002 and 2003, allowing the exploitation and destruction of cloned humans well past the embryonic stage. This approach is now reflected in California's state constitution through voter approval of "Proposition 71" in November 2004: It rejects "human reproductive cloning," defined as using a cloned embryo to initiate a pregnancy if this is done as part of "the practice of creating or attempting to create a human being" (which seems intended to mean a live-born human being). Other states have also continued to consider such legislation.

But why the shift toward "fetus farming"? The answer lies in recent cloning research.

B. The Researchers' Slippery Slope: The Need for Fetal Organs

The shift in legislation is due to a growing realization that human cloning will probably not produce usable cells and tissues unless cloned humans can be developed past the embryonic stage. Five recent studies are of special importance:

  1. The first animal study claiming therapeutic benefits from cloning was published in April 2002.10 It used cells from a cloned mouse embryo to try to reverse an immune deficiency in the original mouse. This effort failed to cure the condition, and showed that even genetically matched embryonic cells from an animal's own clone may be rejected by the animal.11 The researchers succeeded in curing the disease only when they modified stem cells from the cloned embryo (to correct the original mouse's genetic defect), used these stem cells to create a new embryo, then placed that embryo in a mouse's womb to develop it to the newborn stage. The born mouse's adult stem cells were placed back in the original mouse to reverse the disease.12
  2. In June 2002, researchers at Advanced Cell Technology (ACT) in Massachusetts reported on their efforts to use cloning to produce kidney tissue for cows. The effort succeeded only when they placed the cloned cow embryo in a cow's womb, grew it to the fetal stage, then aborted it to obtain developed kidney tissue. The authors pointed out that because this required gestation in a womb, it should not be considered as a model for human "therapeutic cloning."13
  3. In February 2004, ACT reported on its efforts to clone mouse embryos to produce new heart tissue for mice. Once again, usable cells were produced only after the researchers placed the cloned mouse embryos in "surrogate mother" mice, grew them to the late fetal stage (the equivalent of the fifth to sixth month of pregnancy in humans), then aborted them for their heart tissue. This time, however, their report contained no disclaimer about this not being a model for human "therapeutic cloning."14 Even the fact that the study required fetus farming was made clear only in a data supplement on "materials and methods," quietly posted online after ACT's news release about this "advance" had been issued.15 In the news release, ACT hails its study as presenting "an important new paradigm" for therapies, but falsely describes it as involving "myocardial regeneration obtained with stem cells from cloned embryos."16 In fact cloned embryos were grown into cloned fetuses, then aborted for their cells.
  4. In ACT's third study on "therapeutic cloning" in animals, in June 2005, its researchers were more candid. The new study, on producing new blood cells in cows, openly reported that cloning was used to generate "cloned bovine fetuses," and "clone fetal liver hematopoietic stem cells" were transplanted into the cows that provided the original body cells.17 The cow fetuses, whose normal gestation time is similar to that of humans, were aborted at 100-120 days' gestation (3 to 4 months) for their liver tissue.18 While the adult cows developed only very limited "chimerism" (survival of cells from the cloned fetuses), the authors added that "transplantation of whole liver from older cloned fetuses into unconditioned cows would be expected to give significantly higher levels of long-term chimerism."19 ACT's own press release announced that in this study the cloning technique was used "to generate fetal liver hematopoietic stem cells" (which is misleading, since it actually generated mid-term fetuses that were then dissected for their livers). The release quoted chief author Robert Lanza as saying: "We hope to use this technology in the future to treat patients with diverse diseases..."20
  5. A January 2004 study of cloned embryos helps explain why cloning research is taking this alarming direction. It seems the cloning procedure wreaks havoc in gene expression at the embryonic stage – that is, all the human genes are present, but the genes do not always "switch on" and express themselves at the right time and in the right order, and this produces many abnormalities. However, there may be a second opportunity to finish "reprogramming" the genes successfully, if one can get the cloned embryo to survive to the fetal stage.21 This provides a scientific rationale for developing cloned embryos to the fetal stage, to produce more normal cells that are usable in research or therapy.

IV. Conclusion

Cloning supporters in the biotechnology industry are moving on to the next stage of their agenda – one that requires gestation in the womb to grow and then destroy fetal humans for their body parts. They believe use of human cloning for "therapeutic" purposes may require use of what everyone once called "reproductive" cloning.


  1. A group of researchers and ethicists who support cloning for research purposes (which they call CRNT for "cell replacement through nuclear transfer") admits that "the techniques developed in CRNT research can prepare the way scientifically and technically for efforts at reproductive cloning." Robert P. Lanza et al., "The Ethical Validity of Using Nuclear Transfer in Human Transplantation," Journal of the American Medical Association 284 (December 27, 2000): 3175-3179 at 3178. The American Society for Reproductive Medicine (ASRM) says of the same cloning procedure, which it calls SCNT for "somatic cell nuclear transfer": "If undertaken, the development of SCNT for such therapeutic purposes, in which embryos are not transferred for pregnancy, is likely to produce knowledge that could be used to achieve reproductive SCNT." ASRM Ethics Committee, "Human somatic cell nuclear transfer (cloning)," Fertility and Sterility 74 (November 2000): 873-876 at 873;
  2. See: Daniel J. Bryant, Testimony on behalf of the U.S. Department of Justice before the House Government Reform Committee, May 15, 2002,; Richard M. Doerflinger, Testimony on behalf of the U.S. Conference of Catholic Bishops before the Senate Commerce Subcommittee on Science, Technology and Space, March 27, 2003,
  3. Even this bill has an implied threat against a woman who already carries a cloned embryo in her womb. If she continues the pregnancy past 14 days, she could violate federal law and be subject to civil penalties for not aborting before that time. If the pregnancy has continued past 14 days, however, there is no legal penalty for maintaining the fetus to the point of live birth. See Doerflinger, note 2 supra.
  4. Remarks of Michael J. Werner, Esq. on behalf of the Biotechnology Industry Organization to the President's Council on Bioethics, June 12, 2003,
  5. See Illinois Biotechnology Industry Organization, "NOTES: BIO State Government Relations Committee Meeting, March 4, 2003," p. 2;
  6. Cal. Health and Safety Code §125300.
  7. Cal. Health and Safety Code §24185. Also see Americans to Ban Cloning, "Report: State Bills on Human Cloning," March 26, 2003 (emphasis added);
  8. Testimony from Michael J. Werner, Esq. on behalf of the Biotechnology Industry Organization (BIO) in support of New Jersey Senate Bill 1909, Senate Health, Human Service & Senior Citizens Committee, November 4, 2002;
  9. N.J. Stat. Ann. §2C: 11A-1. Also see "Report," note 7 supra.
  10. William M. Rideout III et al., "Correction of a Genetic Defect by Nuclear Transplantation and Combined Cell and Gene Therapy," Cell 109 (April 5, 2002): 17-27.
  11. One set of experts noted that in this study "the donor cells, although derived from the animals with the same genetic background, are rejected by the hosts," and concluded that such "unexpected findings" pose a challenge to future use of embryonic stem cells for therapeutic purposes. Robert Y.L. Tsai et al., "Plasticity, Niches, and the Use of Stem Cells," Developmental Cell 2 (June 2002): 707-712 at 710.
  12. See Americans to Ban Cloning, "Why the 'Successful' Mouse 'Therapeutic' Cloning Really Didn't Work,"
  13. Robert Lanza et al., "Generation of histocompatible tissues using nuclear transplantation," Nature Biotechnology 20 (July 2002): 689-696; The authors declared: "Because the cloned cells were derived from early-stage fetuses, this approach is not an example of therapeutic cloning and would not be undertaken in humans." Id. at 689.
  14. Robert Lanza et al., "Regeneration of the Infarcted Heart With Stem Cells Derived by Nuclear Transplantation," Circulation Research 94 (April 2, 2004): 820-827;
  15. "Cleaved (2-cell) embryos were transferred... to the oviducts of pseudopregnant CD1 surrogate mothers. Cloned fetuses recovered at 11 to 13 days of gestation were used as source of liver cells." Online Data Supplement, at Total gestational period in the mouse is about 20 days long.
  16. See Advanced Cell Technology, "Cloned Stem Cells Regenerate Heart Muscle Following a Heart Attack," February 10, 2004, posted on The Healthcare Sales and Marketing Network;
  17. Robert Lanza et al., "Long-Term Bovine Hematopoietic Engraftment with Clone-Derived Stem Cells," Cloning and Stem Cells 7 (June 2005): 95-106 at 95;
  18. Id. at 96.
  19. Id. at 105 (emphasis added).
  20. Advanced Cell Technology, "Somatic Cell Nuclear Transfer Gives Old Animals Youthful Immune Cells," June 29, 2005;
  21. Josef Fulka et al., "Do cloned mammals skip a reprogramming step?", Nature Biotechnology 22.1 (January 2004): 25-26;