Many people have a strongly held religious conviction that destroying a human embryo is murder.
The first cloning of a human embryo shows how costly copying a sick person's cells would be.
President Clinton has issued an administrative directive that no federal money be spent on human embryo research.
After all, to obtain these stem cells, you must destroy a human embryo.
But are these genes unique to the fly, or do homologous genes determine the development of a human embryo?
The achievement is a long way from creating a cloned human embryo.
But Greenpeace in Germany, which triggered the case, argued it was unethical to issue a patent based on cells from a human embryo.
Advocates of human embryo cloning for medical research claim the practice could lead to the discovery of treatments for illnesses currently deemed incurable.
The first scientists to clone a human embryo admitted today that there were ethical lapses in the way the research was carried out.
The success also provides encouragement that useable stem cells can be found from other sources apart from the human embryo, which remains controversial.
Tooth enamel begins to form in the human embryo when a specialised layer of cells, called ameloblasts, in the embryonic tooth bud secretes amelogenin proteins.
"A human embryo starts out as a single fertilised cell and rapidly divides into a widely complex series of cells that become a human being, " explained Dr McCallion.
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They used stem cells from a human embryo, which are capable of becoming any other type of cell in the human body from nerve to skin, muscle to kidney.
The basic techniques of human embryo creation that Dr. Edwards pioneered form the technical foundation of in vitro fertilization, human cloning techniques, genetic screening of human embryos and embryonic-stem-cell research.
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On Thursday a team of researchers at Newcastle University in the UK, which hopes to join South Korea in the forefront of stem cell research, also said they had successfully cloned an human embryo.
Federal law currently prohibits taxpayer-funded human embryo research.
Dolly the sheep -- the first cloned animal -- was created over 10 years ago, and the only previous claim of human embryo cloning by South Korean scientist Woo Suk Hwang in 2004, was discredited.
The ban was lifted for funding of fetal tissue research in 1993, when promising approaches were proposed for treatment of Parkinson's disease, but the ban on federal funding for human embryo research remains in effect.
The body that regulates IVF clinics in the UK, the Human Fertilisation Embryo Authority (HFEA), concedes that provision is "patchy" in parts of the country but says both sperm and egg donation was falling long before the change in the law.
The birth of the first human child who began life as an embryo outside the human body made headlines world-wide and, within a few years, spawned hundreds of commercial IVF clinics.
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But creating a cloned embryo requires human egg cells, and egg cells aren't cheap.
In a laboratory at Cambridge in 1968, he first saw life created outside the womb in the form of a human blastocyst, an embryo that has developed for five to six days after fertilisation.
The birth of the first child who began life as an embryo outside the human body made headlines world-wide and ultimately spawned hundreds of commercial IVF clinics.
" He admits to being "agnostic" on the question of whether the embryo "is a human being equal to your grandchildren.
Scientific advances such as these put human iPS cells into the same spotlight that embryo-derived hES cells have been under since 2001.
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They regard it as unacceptable that scientists should "sacrifice" an embryo, which has the potential for human life, merely to harvest particular cells.
A. Since the cells must come from an embryo, it often involves the discarding of potential human beings.
The embryo defenders say each of these microscopic balls is a human life that shouldn't be wasted.
But critics of human cloning and stem cell extraction methods essentially believe a human egg that begins to divide for any reason should be considered an embryo, and a potential person, that deserves protection under the law.
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