Cloning 101

Rebecca Taylor
© 2005
Reproduced with Permission
Mary Meets Dolly

Asexual reproduction or cloning

The term "cloning" has been used in biotechnology for a long time and refers to more than one kind of procedure. The cloning procedure most in debate in the scientific world is called somatic cell nuclear transfer (SCNT). A somatic cell is any cell in the body except the egg or sperm cells, or their precursors. Skin cells, blood cells, brain cells are all somatic cells. Every somatic cell contains, in its nucleus, all of the chromosomes (DNA) unique to each individual. In SCNT, a technician takes an egg from a female donor, removes the nucleus, and inserts the somatic cell nucleus with its DNA into the "empty" egg. SCNT is the transfer of the nucleus of a somatic cell to the egg.

Through SCNT, an embryo is created by asexual reproduction rather than sexual reproduction. In sexual reproduction, an egg and sperm meet, each with half the DNA to make a full genome. They combine, and rearrangement of the DNA occurs, creating a unique individual with a unique genome. In SCNT, an egg is impregnated with all 46 chromosomes of an already existing genome, and then is "tricked" into thinking it has been fertilized. The egg begins to divide and a cloned embryo is created.

The development of SCNT naturally gives rise to the question whether a clone, if created asexually (rather than sexually as God intended), is actually a human being. Is a clone but a soulless copy? The Catholic Church teaches that a cloned human embryo is as much a human being as the person who is cloned. Paraphrasing the pertinent section of Donum Vitae (The Vatican Instruction on Respect for Human Life in Its Origin), William E. May, Catholic theologian, writes, "However a child comes into the world, whether as the fruit of a conjugal act or through these technologies, he must be respected as a person and as a gift from God."1

A cloned embryo is actually a "delayed twin" of the individual who donated the somatic cell. But, just as identical twins that share the same DNA are never exactly identical, a cloned embryo will never be an exact copy of the original. Changes in the expression of the genes during development assure that the clone will not be a carbon copy of its predecessor. Also, there is DNA outside of the nucleus in the mitochondria of the egg cell, so the cloned embryo will have some DNA from the egg left in the cell. The cloned embryo will be a hybrid, with DNA from both the cloned individual and the female egg donor.

Therapeutic versus reproductive cloning

Many scientists, ethicists, and legislators try to make a distinction between "therapeutic cloning" and "reproductive cloning." Actually, they are the same thing. They both use SCNT to create a cloned embryo. The difference lies in what happens to that clone. Reproductive cloning is where the cloned embryo is implanted into a surrogate mother, resulting in an infant who is a "delayed twin" of the cloned adult. In therapeutic cloning, the cloned embryo is allowed to divide to the blastocyst stage, then it is destroyed in order to harvest cells of interest, namely embryonic stem cells.

SCNT is often a synonym for therapeutic cloning, and that confuses the general public. No matter what the final goal of the procedure is - therapeutic SCNT or reproductive SCNT - cloning is cloning.

No longer science fiction

Human cloning is now a reality. Scientists in the United States and around the world are currently performing SCNT in an attempt to create cloned human embryos for research. In countries, including the United States, where therapeutic cloning has not been prohibited, researchers are racing to perfect the cloning process. Advanced Cell Technologies has announced that they have successfully cloned a human embryo that grew to the 6-cell stage, but then stopped dividing. South Korean researcher Woo Suk Hwang announced in May 2005 that his team successfully cloned 30 human embryos, grew them to the blastocyst stage, and then destroyed them to create 11 embryonic stem cell lines. Hwang's research has since been discredited, but the race to clone embryos still goes on. Cloniad, a company dedicated to providing reproductive cloning to those who can pay for it, claims that they have produced 13 cloned children, but there is no scientific evidence to substantiate their claims. However, Michael Bishop, a scientist who clones farm animals, says that he has seen pictures of equipment in IVF clinics that is used for cloning. He suggests that IVF clinics are already attempting to produce cloned children. Bishop told Elaine Dewar, an investigative reporter, "We are already cloning people, just not calling them clones. Who's gonna know? …How would you know unless you compared the DNA?"2

Lesser of two evils

Both therapeutic and reproductive cloning are unethical because they create human beings asexually, not sexually as God intended. The majority of society, including many scientists, find reproductive cloning morally reprehensible, and yet many see no problem with therapeutic cloning. Unfortunately, with the perfection of therapeutic cloning comes the likelihood that some one will use that technology for reproductive cloning. Gregory Pence, a bioethicist and cloning advocate, is correct when he writes, "Scientists are nave to think they can ban reproductive cloning and go ahead and study embryonic [therapeutic] cloning."3 President Bush agrees. In a 2002 press conference, he stated that "anything other than a total ban on human cloning would be virtually impossible to enforce. Cloned human embryos created for research would be widely available in laboratories and embryo farms. Once cloned embryos were available, implantation would take place. Even the tightest regulations and strict policing would not prevent or detect the birth of cloned babies."4

Only a handful of states have legislation that addresses SCNT, and many of them permit therapeutic cloning while banning reproductive cloning. As of the fall of 2005, the Federal government has no legislation on SCNT. Currently, the Feinstein-Hatch bill in Congress seeks to legalize cloning for medical research purposes and, at the same time, ban reproductive cloning. Any legislation that permits SCNT for research, yet bans cloning to produce children, is particularly reprehensible because it requires that any human life created by cloning must be destroyed for research purposes. While the thought of producing cloned children puts many Americans over the edge, it is therapeutic cloning that is the more insidious technology. Therapeutic cloning "creates" human life and mandates that it be destroyed. The more ethical choice would be to implant a cloned embryo into a surrogate mother, rather than destroy it for its stem cells.

The only way to prevent cloning and the creation of human life slated for destruction is to ban all SCNT in humans. A bill by Senator Sam Brownback (R-KS) and Senator Mary Landrieu (D-LA), supported by President Bush, would ban all human cloning for research, as well as for producing children. This bill has passed the House of Representatives but has stalled in the Senate. Senator Landrieu recognizes the dangers in using SCNT in humans for any purpose. That is why she has correctly stated, "Cloning is cloning. That is why it should all be illegal."5


1 William E. May, Catholic Bioethics and the Gift of Human Life, Our Sunday Visitor, Inc., Huntington, IN, p. 37 [Back]

2 Elaine Dewar, The Second Tree: Stem Cells, Clones, Chimeras, and the Quest for Immortality, Carroll & Graf Publishers, New York, p. 162 [Back]

3 Gregory E. Pence, Cloning after Dolly: Who's Still Afraid?, Rowman & Littlefield Publishers, 2004, p. 72 [Back]

4 George W. Bush, [Back]

5 Gregory E. Pence, Cloning after Dolly: Who's Still Afraid?, p. 69 [Back]