Is embryo cloning moral?
Cloning of animals seems to have a number of potentially positive results:
Scientists are attempting to create transgenic pigs which have human genes. Their heart, liver or kidneys might be useable as organ transplants in humans. This would save many lives; thousands of people die each year waiting for available human organs. Once achieved, transgenic animals could be cloned to produce as many organs as are needed.
Experience gained in cloning may add to our understanding of genetics.
Researchers have produced transgenic animals. These are genetically altered, typically in order to produce human hormones or proteins in its milk. These materials can be separated from the milk and used to heal humans. Cloning would produce as many genetically altered animals as are needed. The alternative is to simply allow them to mate; this would produce many offspring that had lost the inserted human gene and thus would be unable to produce the medication.

Labels: Cloning of animals

Cloning of embryos has been used in mice experiments since the late 1970's, and in animal breeding since the late 1980's. The procedure splits a single fertilized ovum into two or more clones, each of which is then implanted into the womb of a receptive female.
However, research into cloning of human embryos has been restricted in the United States and in some other countries. Pro-life groups which oppose free access to abortion have had considerable political power. They were able to have all human embryo research banned by the Regan and Bush Presidencies during most of the 1980's and into the early 1990's. During the first few days of President Clinton's presidency, the ban on public funding of human embryo and fetal research was lifted.
We may not know the individual or team who first performed cloning of human embryos. The methods used have been understood for many years and actually used to clone embryos in cattle and sheep. It is likely that someone had successfully used the method on a human embryo in secret. The first publicly announced human cloning was done by Robert J. Stillman and his team at the George Washington Medical Center in Washington D.C. They took 17 genetically flawed human embryos which would have died within days no matter how they were treated. They were derived from an ovum that had been fertilized by two sperm. This resulted in an extra set of chromosomes which doomed the ovum's future. None could have developed into a fetus. These ovum were successfully split in 1994-OCT, each producing one or more clones. The main motive of the experiment seems to have been to trigger public debate on the ethics of human cloning.
Dr. Steven Muller headed a panel in the US whose mandate was to produce preliminary cloning guidelines. These would be used by the Federal National Institutes of Health to decide which cloning research to fund. The panel recommended that studies be normally limited to the use of preexisting, spare embryos - those that developed during in vitro fertilization procedures that had been performed to assist couples in conceiving. Generally about 20 or 24 ova are fertilized during these procedures. Only three or four are implanted in the woman. The extra zygotes are either discarded or frozen for possible future use. New embryos would only be prepared and used if needed for "compelling research." They further recommended that any studies be normally terminated within 14 days of conception. Some experiments might be authorized to continue until the 18th day, but no further. At that gestational age, neural tube closure begins; this is the start of the development of a nervous system. They recommended that certain procedures be banned, including implanting human embryos in other species, implanting cloned embryos into humans, the transfer of a nucleus from one embryo to another, and the use of embryos for sex selection.

Labels: Embryo cloning

Human embryo cloning starts with a standard in vitro fertilization procedure. Sperm and an egg cell are mixed together on a glass dish. After conception, the zygote (fertilized egg) is allowed to develop into a blastula (a hollow mass of cells). The zygote divides first into two cells, then four, then eight... A chemical is added to the dish to remove the "zona pellucida" covering. This material provides nutrients to the cells to promote cell division. With the covering removed, the blastula is divided into individual cells which are deposited on individual dishes. They are then coated with an artificial zona pellucida and allowed to divide and develop. The experiment by Sillman et al. showed that the best results could be obtained by interrupting the zygote at the two cell stage. Many of these pairs of zygotes were each able to develop to the 32 cell stage, but stalled at that point. They might well have had the potential to develop further and even mature into a viable fetus, except that the original ovum was defective and would have died anyway. For ethical reasons, the researchers had selected embryos which had no possibility of ever maturing into fetuses, and thus becoming newborn babies.

Labels: Human embryo cloning

Cloning is the production of one or more individual plants or animals that are genetically identical to another plant or animal.
Embryo cloning might be more accurately called "artificial twinning", because it simulates the mechanism by which twins naturally develop. It involves removing one or more cells from an embryo and encouraging the cell to develop into a separate embryo with the same DNA as the original. It has been successfully carried out for years on many species of animals. Some very limited experimentation has been done on human embryos.Nature itself is the greatest cloning agent. In about one of every 75 human conceptions, the fertilized ovum splits for some unknown reason and produces monozygotic (identical) twins. Each has an genetic makeup identical to the other. In cloning, this same operation is done intentionally in a laboratory.

Plant biotechnology: Plant Biotechnology Reproduction and propagation