Cloning

The concept cloning refers to artificial embryo twinning, somatic cell nuclear transfer, and removing stem cells from embryos and adult individuals to be used to “grow” tissues, organs, or individuals. Embryonic cloning involves using an electric current or other technique to split a preembryo into two, each of which has the potential, under optimal circumstances, of gestation and parturition to develop into a member of the species. The more powerful technique of somatic cell nuclear transfer involves the removal of the nucleus of an unfertilized ovum and replacing it with the nucleus of a somatic cell, such as a skin cell, and then using a small electric current to cause these combined elements to reverse the specialization and revert to stem cell status. The resultant cell is somewhat like a fertilized ovum, except that the bulk of its DNA is that of the donor organism with the exception of the mitochondrial DNA that comes from the ovum. Finally, one goal of human therapeutic cloning is to produce cells that are [Page 203]progenitors of those for specific organs, not entire organisms. Such cloning is commonly referred to as therapeutic cloning: the cloning of organs and tissues that are histocompatible with a potential recipient of a transplantation of the resultant cells or organ. To date, cloning as a technique is in its infancy. Medical science has little interest in cloning individuals or in artificial twinning. The major thrust is toward human therapeutic cloning.

Cloning and Death

The prospect of death, whether of oneself or a loved one, frightens most humans. The fear may involve various dreadful prospects supposed to await the dying person, from hell's fires, to the pain of separation, to the experience of nothingness. Even those not burdened by belief in an afterlife of judgment seek to remain alive as long as life holds a positive balance of meaningful activity.

Humans have long sought to extend life and forestall death by imprecations, pharmacological supplementation of essential physiological chemicals, surgical removal of tumors, and repair of injuries. In pursuit of longevity humans will cut calories to close to a starvation regimen, ingest unproven and disproven drugs (like laetrile), employ useless procedures (like coffee enemas), and take combinations of substances (like mega-vitamin therapy) believed through a combination of anecdote, assurances, and gullibility to beat back cancers and other life-threatening conditions. More recently, replacement of organs with transplants from donors, living and dead, human and animal, have become the more scientific tools of life extension. Modern medicine and its alternative imitators have become the first and last hope of the sick and dying.

The relatively recent emergence of human reproductive cloning techniques has added several other stratagems to the tempting arsenal of weapons against imminent death. This entry discusses the present technology of human reproductive cloning and the possibilities of human therapeutic cloning for replacement of lost or injured parts and for replication of highly valued individuals.

Cloning and Immortality

Some individuals view cloning as a kind of immortality. But such views are not consistent with the facts. A clone is a much younger twin of the cloned individual. Just as, when a twin dies, it is not claimed that he or she somehow lives on in the survivor, so it wouldn't be said of a clone that he or she is “the spittin' image,” or exact duplicate or replica, of the source of the cloned DNA. The reason is that a clone would be raised by different parents in a different time with different influences on its development. Identity has as much to do with the specifics of time and place as it does with genetic endowment.

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