Stem cell controversy

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The stem cell controversy is the ethical debate centered on research involving the creation, usage and destruction of human embryonic stem cells. Not all stem cell research involves the creation, usage and destruction of human embryos. Extraction of such cells using current technology research represents a social and ethical challenge.


[edit] Stem cells

gene therapy]]). Yet further treatments using stem cells could potentially be developed thanks to their ability to repair extensive tissue damage.[1]

Much success and potential has been demonstrated from research using adult stem cells. There are no approved treatments or human trials using embryonic stem cells. Nevertheless, some researchers are of the opinion that the differentiation potential of embryonic stem cells is broader than most adult stem cells. Embryonic stem cells can become all cell types of the body because they are Totipotent. Adult stem cells are generally limited to differentiating into different cell types of their tissue of origin. However, some evidence suggests that adult stem cell plasticity may exist, increasing the number of cell types a given adult stem cell can become. In addition, embryonic stem cells are considered more useful for nervous system therapies, because researchers have struggled to identify and isolate neural progenitors from adult tissues. Embryonic stem cells, however, might be rejected by the immune system - a problem which wouldn't occur if the patient received his or her own stem cells.

[edit] Alternative sources

Some stem cell researchers are working to develop techniques of isolating stem cells that are as potent as embryonic stem cells, but do not require a human embryo.

Some believe that human skin cells can be coaxed to "de-differentiate" and revert to an embryonic state. Researchers at Harvard University, led by Kevin Eggan, have attempted to transfer the nucleus of a somatic cell into an existing embryonic stem cell, thus creating a new stem cell line.[2] Another study published in August 2006 also indicates that differentiated cells can be reprogrammed to an embryonic-like state by introducing four specific factors, resulting in induced pluripotent stem cells.[3]

Researchers at Advanced Cell Technology, led by Robert Lanza, reported the successful derivation of a stem cell line using a process similar to preimplantation genetic diagnosis, in which a single blastomere is extracted from a blastocyst.[4] At the 2007 meeting of the International Society for Stem Cell Research (ISSCR) [5], Lanza announced that his team had succeeded in producing three new stem cell lines without destroying the parent embryos. "These are the first human embryonic cell lines in existence that didn't result from the destruction of an embryo." Lanza is currently in discussions with the National Institutes of Health (NIH) to determine whether the new technique sidesteps U.S. restrictions on federal funding for ES cell research.[6]

According to a January 9, 2007 Daily Telegraph (London) article reporting on a statement by Dr. Anthony Atala of Wake Forest University, the fluid surrounding the fetus has been found to contain stem cells, that, when utilized correctly, "can be differentiated towards cell types such as fat, bone, muscle, blood vessel, nerve and liver cells", according to the article. The extraction of this fluid is not thought to harm the fetus in any way. "Our hope is that these cells will provide a valuable resource for tissue repair and for engineered organs as well," said Dr Atala.[7]

[edit] Patents

The patents covering a lot of work on human embryonic stem cells are owned by the Wisconsin Alumni Research Foundation (WARF). WARF does not charge academics to study human stem cells but does charge commercial users. WARF sold Geron Corp. exclusive rights to work on human stem cells but later sued Geron Corp. to recover some of the previously sold rights. The two sides agreed that Geron Corp. would keep the rights to only three cell types. In 2001 WARF came under public pressure to widen access to human stem-cell technology.[8]

These patents are now in doubt as a request for review by the US Patent and Trademark Office has been filed by non-profit patent-watchdogs The Foundation for Taxpayer & Consumer Rights and the Public Patent Foundation as well as molecular biologist Jeanne Loring of the Burnham Institute. According to them, two of the patents granted to WARF are invalid because they cover a technique published in 1993 for which a patent had already been granted to an Australian researcher. Another part of the challenge states that these techniques, developed by James A. Thomson, are rendered obvious by a 1990 paper and two textbooks.

The outcome of this legal challenge is particularly relevant to the Geron Corp. as it can only license patents that are upheld.[9][10]

[edit] Viewpoints

The status of the human embryo and human embryonic stem cell research is a controversial issue as, with the present state of technology, the creation of a human embryonic stem cell line requires the destruction of a human embryo. Stem cell debates have motivated and reinvigorated the pro-life movement, whose members are concerned with the rights and status of the embryo as an early-aged human life. They believe that embryonic stem cell research instrumentalizes and violates the sanctity of life and is tantamount to murder.[11] The fundamental assertion of those who oppose embryonic stem cell research is the belief that human life is inviolable, combined with the fact that human life begins when a sperm cell fertilizes an egg cell to form a single cell. (see Sexual reproduction)

A portion of stem cell researchers use embryos that were created but not used in in vitro fertility treatments to derive new stem cell lines. Most of these embryos are to be destroyed, or stored for long periods of time, long past their viable storage life. In the United States alone, there have been estimates of at least 400,000 such embryos.[12] This has led some opponents of abortion, such as Senator Orrin Hatch, to support human embryonic stem cell research.[13] See Also Embryo donation.

Medical researchers widely submit that stem cell research has the potential to dramatically alter approaches to understanding and treating diseases, and to alleviate suffering. In the future, most medical researchers anticipate being able to use technologies derived from stem cell research to treat a variety of diseases and impairments. Spinal cord injuries and Parkinson's disease are two examples that have been championed by high-profile media personalities (for instance, Christopher Reeve and Michael J. Fox). The anticipated medical benefits of stem cell research add urgency to the debates, which has been appealed to by proponents of embryonic stem cell research.

In August, 2000, The U.S. National Institutes of Health's Guidelines stated:

"...research involving human pluripotent stem cells...promises new treatments and possible cures for many debilitating diseases and injuries, including Parkinson's disease, diabetes, heart disease, multiple sclerosis, burns and spinal cord injuries. The NIH believes the potential medical benefits of human pluripotent stem cell technology are compelling and worthy of pursuit in accordance with appropriate ethical standards." [14]

In 2006, researchers at Advanced Cell Technology of Worcester, Mass., succeeded in obtaining stem cells from mouse embryos without destroying the embryos.[15] If this technique and its reliability are improved, it would alleviate some of the ethical concerns related to embryonic stem cell research.

Another technique announced in 2007 may also defuse the longstanding debate and controversy. Research teams in the United States and Japan have developed a simple and cost effective method of reprogramming human skin cells to function much like embryonic stem cells by introducing artificial viruses. While extracting and cloning stem cells is complex and extremely expensive, the newly discovered method of reprogramming cells is much cheaper. However, the technique may disrupt the DNA in the new stem cells, resulting in damaged and cancerous tissue. More research will be required before non-cancerous stem cells can be created.[16][17][18][19]

[edit] Endorsement

[edit] Utilitarianism

The benefits of stem cell research outweigh the cost in terms of embryonic life citation needed

  • Embryonic stem cells have the potential to grow indefinitely in a laboratory environment and can differentiate into almost all types of bodily tissue. This makes embryonic stem cells a prospect for cellular therapies to treat a wide range of diseases.[20]

[edit] Human potential and humanity

This argument often goes hand-in-hand with the utilitarian argument, and can be presented in several forms:

  • Embryos are not equivalent to human life while they are still incapable of surviving outside the womb (i.e. they only have the potential for life).
  • More than a third of zygotes do not implant after conception.[21][22] Thus, far more embryos are lost due to chance than are proposed to be used for embryonic stem cell research or treatments.
  • Blastocysts are a cluster of human cells that have not differentiated into distinct organ tissue; making cells of the inner cell mass no more "human" than a skin cell.[20]
  • Some parties contend that embryos are not humans, believing that the life of Homo sapiens only begins when the heartbeat develops, which is during the 5th week of pregnancy,[23] or when the brain begins developing activity, which has been detected at 54 days after conception.[24]

[edit] Efficiency

If an embryo is going to be destroyed anyway, isn't it more efficient to make practical use of it? citation needed

  • In vitro fertilization (IVF) generates large numbers of unused embryos (e.g. 70,000 in Australia alone).[20] Many of these thousands of IVF embryos are slated for destruction. Using them for scientific research utilizes a resource that would otherwise be wasted.[20]
  • While the destruction of human embryos is required to establish a stem cell line, no new embryos have to be destroyed to work with existing stem cell lines. It would be wasteful not to continue to make use of these cell lines as a resource.[20]
  • Abortions are legal in many countries and jurisdictions. A logical argument follows that if these embryos are being destroyed anyway, why not use them for stem cell research or treatments?

[edit] Superiority

Embryonic stem cells can be considered far more useful therapeutically than adult stem cells citation needed

This is usually presented as a counter-argument to using adult stem cells as an alternative that doesn't involve embryonic destruction.

  • Embryonic stem cells make up a significant proportion of a developing embryo, while adult stem cells exist as minor populations within a mature individual (e.g. in every 1,000 cells of the bone marrow, only 1 will be a usable stem cell). Thus, embryonic stem cells are likely to be easier to isolate and grow ex vivo than adult stem cells.[20]
  • Embryonic stem cells divide more rapidly than adult stem cells, potentially making it easier to generate large numbers of cells for therapeutic means. In contrast, adult stem cell might not divide fast enough to offer immediate treatment.[20]
  • Embryonic stem cells have greater plasticity, potentially allowing them to treat a wider range of diseases.[20]
  • Adult stem cells from the patient's own body might not be effective in treatment of genetic disorders. Allogeneic embryonic stem cell transplantation (i.e. from a healthy donor) may be more practical in these cases than gene therapy of a patient's own cell.[20]
  • DNA abnormalities found in adult stem cells that are caused by toxins and sunlight may make them poorly suited for treatment.[20]
  • Embryonic stem cells have been shown to be effective in treating heart damage in mice.[20]

[edit] Beginning of life

  • Before the primitive streak is formed when the embryo attaches to the uterus at approximately 14 days after fertilization, a single fertilized egg can split in two to form identical twins, or a pair of embryos that would have resulted in fraternal twins can fuse together and develop into one person (a tetragametic chimera). Since a fertilized egg has the potential to be two individuals or half of one, some believe it can only be considered a potential person, not an actual one. Those who subscribe to this belief then hold that destroying a blastocyst for embryonic stem cells is ethical. [25]

[edit] Objection

[edit] Value of life

The deliberate destruction of a human embryo is typically interpreted as being incompatible with Roman Catholic doctrine. Based upon these interpretations, some Catholics have suggested that human blastocysts are inherently valuable and should not be voluntarily destroyed.[26]

Viability is another standard under which embryos and fetuses have been regarded as human lives. In the United States, the 1973 Supreme Court case of Roe v. Wade concluded that viability determined the permissibility of abortions performed for reasons other than the protection of the woman's health, defining viability as the point at which a fetus is "potentially able to live outside the mother's womb, albeit with artificial aid."[27] The point of viability was 24 to 28 weeks when the case was decided and has since moved to about 22 weeks due to advancement in medical technology.

[edit] Better alternatives

This argument is used by opponents of embryonic destruction as well as researchers specializing in adult stem cell research.

It is often claimed by pro-life supporters that the use of adult stem cells from sources such as umbilical cord blood has consistently produced more promising results than the use of embryonic stem cells.[28] Furthermore, adult stem cell research may be able to make greater advances if less money and resources were channeled into embryonic stem cell research.[29]

Adult stem cells have already produced therapies, while embryonic stem cells have not.[30][31] Moreover, there have been many advances in adult stem cell research, including a recent study where pluripotent adult stem cells were manufactured from differentiated fibroblast by the addition of specific transcription factors. [32] Newly created stem cells were developed into an embryo and were integrated into newborn mouse tissues, analogous to the properties of embryonic stem cells.

This argument remains hotly debated on both sides. Those critical of embryonic stem cell research point to a current lack of practical treatments, while supporters argue that advances will come with more time and that breakthroughs cannot be predicted.

[edit] Scientific challenge

One study suggests that autologous embryonic stem cells generated for therapeutic cloning may still suffer from immune rejection.[33]

[edit] Misuse

A recent report has suggested that careless use of fetal stem cells can result in uncontrolled cell growth in the form of tumors.[34]

[edit] Stated views of groups

[edit] Governmental policy stances in Europe

Austria, Denmark, France, Germany, and Ireland do not allow the production of embryonic stem cell lines [35], but the creation of embryonic stem cell lines is permitted in Finland, Greece, the Netherlands, Sweden, and the United Kingdom. [35]

[edit] Governmental Policy debate in the United States

By executive order on March 9, 2009, President Barack Obama removed certain restrictions on federal funding for research involving new lines of human embryonic stem cells. Prior to President Obama's executive order, federal funding was limited to non-embryonic stem cell research and embryonic stem cell research based upon embryonic stem cell lines in existence prior to August 9, 2001. Federal funding originating from current appropriations to the Department of Health and Human Services (including the National Institutes of Health) under the Omnibus Appropriations Act for FY2009, remains prohibited under the Dickey Amendment for (1) the creation of a human embryo for research purposes; or (2) research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death greater than that allowed for research on fetuses in utero.

In a speech before signing the executive order, Mr. Obama noted the following:

President Obama lifts federal funding restrictions on stem cell research.
Today, with the Executive Order I am about to sign, we will bring the change that so many scientists and researchers; doctors and innovators; patients and loved ones have hoped for, and fought for, these past eight years: we will lift the ban on federal funding for promising embryonic stem cell research. We will vigorously support scientists who pursue this research. And we will aim for America to lead the world in the discoveries it one day may yield.[36]

Congressman Jim Langevin, who was paralyzed at age sixteen, was notably present at the signing of the executive order.[37]

[edit] Origins

In 1973, Roe v. Wade legalized abortion nationwide. Five years later, the first successful human in vitro fertilization resulted in the birth of Louise Brown in England. These developments prompted the federal government to create regulations barring the use of federal funds for research that experimented on human embryos. In 1995, the NIH Human Embryo Research Panel advised the administration of President Bill Clinton to permit federal funding for research on embryos left over from in vitro fertility treatments and also recommended federal funding of research on embryos specifically created for experimentation. In response to the panel's recommendations, the Clinton administration, citing moral and ethical concerns, declined to fund research on embryos created solely for research purposes,[38] but did agree to fund research on left-over embryos created by in vitro fertility treatments. At this point, the Congress intervened and passed the Dickey Amendment in 1995 (the final bill, which included the Dickey Amendment, was signed into law by Bill Clinton) which prohibited any federal funding for the Department of Health and Human Services be used for research that resulted in the destruction of an embryo regardless of the source of that embryo.

In 1998, privately funded research led to the breakthrough discovery of Human Embryonic Stem Cells (hESC). This prompted the Clinton Administration to re-examine guidelines for federal funding of embryonic research. In 1999, the president's National Bioethics Advisory Commission recommended that hESC harvested from embryos discarded after in vitro fertility treatments, but not from embryos created expressly for experimentation, be eligible for federal funding. Even though embryos are always destroyed in the process of harvesting hESC, the Clinton Administration decided that it would be permissible under the Dickey Amendment to fund hESC research as long as such research did not itself directly cause the destruction of an embryo. Therefore, HHS issued its proposed regulation concerning hESC funding in 2001. Enactment of the new guidelines was delayed by the incoming George W. Bush administration which decided to reconsider the issue.

President Bush announced, on August 9, 2001 that federal funds, for the first time, would be made available for hESC research on currently existing stem cell lines. President Bush authorized research on existing human embryonic stem cell lines, not on human embryos under a specific, unrealistic timeline in which the stem cell lines must have been developed. However, the Bush Administration chose not to permit taxpayer funding for research on hESC cell lines not currently in existence, thus limiting federal funding to research in which "the life-and-death decision has already been made".[39] The Bush Administration's guidelines differ from the Clinton Administration guidelines which did not distinguish between currently existing and not-yet-existing hESC. Both the Bush and Clinton guidelines agree that the federal government should not fund hESC research that directly destroys embryos.

Neither Congress nor any administration has ever prohibited private funding of embryonic research. Public and private funding of research on adult and cord blood stem cells is unrestricted.[40]

[edit] U.S. Congressional response

In April 2004, 206 members of Congress signed a letter urging President Bush to expand federal funding of embryonic stem cell research beyond what Bush had already supported.

In May 2005, the House of Representatives voted 238-194 to loosen the limitations on federally funded embryonic stem-cell research — by allowing government-funded research on surplus frozen embryos from in vitro fertilization clinics to be used for stem cell research with the permission of donors — despite Bush's promise to veto the bill if passed.[41] On July 29, 2005, Senate Majority Leader William H. Frist (R-TN), announced that he too favored loosening restrictions on federal funding of embryonic stem cell research.[42] On July 18, 2006, the Senate passed three different bills concerning stem cell research. The Senate passed the first bill (Stem Cell Research Enhancement Act), 63-37, which would have made it legal for the Federal government to spend Federal money on embryonic stem cell research that uses embryos left over from in vitro fertilization procedures.[43] On July 19, 2006 President Bush vetoed this bill. The second bill makes it illegal to create, grow, and abort fetuses for research purposes. The third bill would encourage research that would isolate pluripotent, i.e., embryonic-like, stem cells without the destruction of human embryos.

In 2005 and 2007, Congressman Ron Paul introduced the Cures Can Be Found Act,[44] with 10 cosponsors. With an income tax credit, the bill favors research upon non embryonic stem cells obtained from placentas, umbilical cord blood, amniotic fluid, humans after birth, or unborn human offspring who died of natural causes; the bill was referred to committee. Paul argued that hESC research is outside of federal jurisdiction either to ban or to subsidize.[45]

Bush vetoed another bill, the Stem Cell Research Enhancement Act of 2007,[46] which would have amended the Public Health Service Act to provide for human embryonic stem cell research. The bill passed the Senate on April 11 by a vote of 63-34, then passed the House on June 7 by a vote of 247-176. President Bush vetoed the bill on July 19, 2007.[47]

On March 9, 2009, President Obama repealed a ban enacted under President Bush, [48] thus allowing federal funds to be applied beyond what was authorized for funding under the previous president. Two days after Obama reversed the ban, the President then signed the Omnibus Appropriations Act of 2009, which still contained the long-standing Dickey-Wicker provision which bans federal funding of "research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death;"[49] the Congressional provision effectively prevents federal funding being used to create new stem cell lines by many of the known methods. So, while scientists might not be free to create new lines with federal funding, President Obama's policy allows the potential of applying for such funding into research involving the hundreds of existing stem cell lines as well as any further lines created using private funds or state-level funding. The ability to apply for federal funding for stem cell lines created in the private sector is a significant expansion of options over the limits imposed by President Bush, who restricted funding to the 21 viable stem cell lines that were created before he announced his decision in 2001.[50]

[edit] Funding

Currently, the National Institutes of Health has 399 funding opportunities for researchers interested in hESC.[citation needed] In 2005 the NIH funded $607 million worth of stem cell research, of which $39 million was specifically used for hESC.[51] Of the 514 currently recruiting clinical trials that are using stem cells as treatment, the federal government is supporting 206 of them; however, none of these trials are using hESC.[citation needed] Sigrid Fry-Revere has argued that private organizations, not the federal government, should provide funding for stem-cell research, so that shifts in public opinion and government policy would not bring valuable scientific research to a grinding halt[52]

In 2005 the State of California took out 3 billion dollars in bond loans to fund embryonic stem cell research in that state.[53]

[edit] See also

[edit] References

  1. ^ Stem Cells for Tissue Regeneration and Joint Repair Science Daily 29th march 2006.
  2. ^ C.Cowan, J. Atienza, D. Melton and K. Eggan. (August 26, 2005) "Nuclear reprogramming of somatic cells after fusion with human embryonic stem cells." Science, 309:1369.
  3. ^ Takahashi K and Yamanaka S (2006). "Induction of Pluripotent Stem Cells from Mouse Embryonic and Adult Fibroblast Cultures by Defined Factors". Cell 126: 663–676. doi:10.1016/j.cell.2006.07.024. 
  4. ^ Irina Klimanskaya, Young Chung, Sandy Becker, Shi-Jiang Lu & Robert Lanza. (August 23, 2006) "Human embryonic stem cell lines derived from single blastomeres." Nature. doi:10.1038.
  5. ^ ABC News: ABC News
  6. ^ ScienceNOW - Sign In
  7. ^ Clout, Laura; and Agencies (2007-09-01). ""Scientists report alternative stem cell source"". Daily Telegraph (UK). Retrieved on 2007-09-20. 
  8. ^ Regalado, Antonio, David P. Hamilton (July 2006). "How a University's Patents May Limit Stem-Cell Researcher." Wall Street Journal. Retrieved on July 24, 2006.
  9. ^ Kintisch, Eli (July 18, 2006) "Groups Target Stem Cell Patents." ScienceNOW Daily News. Retrieved August 15, 2006.
  10. ^ Associated Press. (July 19, 2006) "Stem Cell Patents Come Under Fire." Retrieved August 15, 2006.
  11. ^ "The stated reason for President Bush's objection to embryonic stem cell research is that 'murder is wrong'" (BBC)
  12. ^ Weiss, Rick. (May 8, 2003) "400,000 Human Embryos Frozen in U.S.," Washington Post. Retrieved August 24, 2006.
  13. ^ Connolly, Ceci. (July 30, 2005) "Frist Breaks With Bush On Stem Cell Research." Washington Post. Retrieved August 24, 2006.
  14. ^ "NIH Publishes Final Guidelines for Stem Cell Research". National Institutes of Health. 2000. Retrieved on 2007-04-29. 
  15. ^ "Deriving Stem Cells Without Killing Embryo". Medical News Today. 2006. Retrieved on 2007-12-26. 
  16. ^ "New stem cell breakthrough". 2007.$1169327.htm. Retrieved on 2007-12-26. 
  17. ^ "Biologists Make Skin Cells Work Like Stem Cells". The New York Times. 2007. Retrieved on 2007-12-26. 
  18. ^ "Scientists Use Skin To Create Stem Cells". The Washington Post. 2007. Retrieved on 2007-12-26. 
  19. ^ "Scientists Convert Mouse Skin Cells to Stem Cells". Public Broadcasting Service. 2007. Retrieved on 2007-12-26. 
  20. ^ a b c d e f g h i j k "Arguments For Stem cell Research". Spinneypress. 2006. Retrieved on 2007-12-26. 
  21. ^ Raymond J. Devettere. Practical Decision Making in Health Care Ethics
  22. ^ Kathleen Stassen Berger. The Developing Person Through the Life Span
  23. ^ Greenfield, Marjorie. “Dr.". Retrieved 2007-01-20.
  24. ^ Singer, Peter. Rethinking life & death: the collapse of our traditional ethics, page 104 (St. Martins Press 1996). Retrieved 2007-03-04.
  25. ^ West, Michael D.(2005) The Ethics of Genetic Engineering (At Issue Series). (pp 100-107) USA: Thomson Gale
  26. ^ Prof. Juan de Dios Vial Correa, S.E. Mons. Elio Sgreccia (2000-8-25). "Scientific and Therapeutic Use of Human Embryonic Stem Cells". Vatican City: Libreria Editrice Vaticana. Retrieved on 2008-2-20. 
  27. ^ Roe v. Wade, 410 U.S. 113 (1973). Retrieved 2007-05-15
  28. ^ Prentice, David. (October 17, 2005) "Live Patients & Dead Mice". Christianity Today. Retrieved on August 24, 2006.
  29. ^ The Coalition of Americans for Research Ethics. "The "Political Science" of Stem Cells". Retrieved on July 16, 2006.
  30. ^ Clarke, Michael F. and Michael W. Becker. (July 2006). "Stem Cells: The Real Culprits in Cancer?" Scientific American. Retrieved on August 8, 2006.
  31. ^ Anonymous (September 24, 2006) "Cloning/Embryonic Stem Cells." National Human Genome Research Institute. Retrieved September 24, 2006.
  32. ^ Cyranoski. "Simple switch turns cells embryonic". Nature 6 June 2007. 
  33. ^ Americans for Banning Cloning.(2002) [ "Why the "Successful" Mouse "Therapeutic" Cloning Really Didn't Work. "] Stem Cell Research. Retrieved April 13, 2007.
  34. ^ [Report: Fetal stem cells trigger tumors in ill boy]
  35. ^ a b "As noted before, the production of hESC lines is currently illegal in Germany; the 1990 Embryo Protection Act prohibits any utilization of the embryo that does not serve its preservation. ... Ireland, Austria, Denmark and France prohibit any production of hESC lines...Finland, Greece, the Netherlands, Sweden and the UK allow the production of hESC lines from surplus IVF embryos."Peter M. Wiedemann, Judith Simon, Silke Schicktanz & Christof Tannert (2004). "The future of stem-cell research in Germany". Nature and the European Molecular Biology Organization. 
  36. ^ A debt of gratitude to so many tireless advocates
  37. ^ A debt of gratitude to so many tireless advocates
  38. ^ ""President Clinton's Comments on NIH and Human Embryo Research"". U.S. National Archives. Retrieved on 2006-07-19. 
  39. ^ The White House, Press Release, August 9, 2001
  40. ^
  41. ^ "A Step Closer to Stem-Cell Heaven". Wired. 2005.,1286,67627,00.html. Retrieved on 2008-02-28. 
  42. ^ Connolly, Ceci (of work = July 30, 2005). ""Despite Bush Veto, Stem Cell Research Abounds"". Washington Post: A01. Retrieved on 2006-07-21. 
  43. ^ Kellman, Laurie. ""Senate Approves Embryo Stem Cell Bill"". Associated Press. Retrieved on 2006-07-18. 
  44. ^ H.R. 457, 110th Congress
  45. ^ "Rights of Taxpayers is Missing Element in Stem Cell Debate". The Ron Paul Library. 
  46. ^ S. 5
  47. ^ "Senate Approves Embryonic Stem Cell Bill", David Espo, Associated Press, April 12, 2007
  48. ^ "Obama overturns Bush policy on stem cells" CNN, March 9, 2009
  49. ^ Obama's Stem Cell Policy Hasn't Reversed Legislative Restrictions, Fox News, March 14, 2009
  50. ^ Aldhous, Peter (March 2009). "Obama lifts research restrictions on embryonic stem cells". Reed Business Information Ltd. Retrieved on 2009-03-16. "This frees biologists to work with a wide range of human ESCs - including cell lines created with state and private funding. But researchers are not expected to be able to use federal grants to create new cell lines. This is because of a 1996 law called the Dickey-Wicker amendment..." 
  51. ^ "Estimates of Funding for Various Diseases, Conditions, Research Areas". National Institutes of Health. 2007. Retrieved on 2008-01-21. 
  52. ^ "Best Hope Lies in Private Stem-Cell Funding". Retrieved on 2008-01-31. 
  53. ^

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